Sound-absorbing material and method for producing the same

Abstract

This invention belongs to the field of acoustic materials technology and discloses a sound-absorbing material and its preparation method. The sound-absorbing material includes a core layer and a surface layer; the core layer comprises a composite material formed by intercalating meltblown ultrafine fibers with hollow elastic short fibers; the surface layer has two layers, which are respectively applied to opposite sides of the core layer, and each surface layer comprises a flash-evaporated nonwoven fabric, forming a three-layer structure with the core layer. In the sound-absorbing material provided by this invention, the waterproof and breathable properties, as well as the good mechanical and protective properties of the flash-evaporated nonwoven fabric, are utilized to improve the performance defects of short-fiber intercalated meltblown nonwoven sound-absorbing cotton, resulting in a sound-absorbing material with advantages such as waterproof and breathable properties, good sound absorption performance, high mechanical properties, and mildew resistance, thus improving the service life of the sound-absorbing material.

Description

Technical Field

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

[0002] With the rapid development of urbanization, transportation, and industry, people are facing increasingly serious noise pollution problems and the serious health risks they pose. Long-term exposure to noise can not only cause varying degrees of hearing impairment but also trigger multiple stress responses. Therefore, noise control is receiving increasing attention from the public and society. The implementation of strict noise pollution measures and the growing awareness of the harmful effects of noise have promoted the widespread use of sound-absorbing materials in construction, automotive, transportation, and industrial fields.

[0003] Porous sound-absorbing materials are among the most widely used sound-absorbing materials, mainly including sound-absorbing foam and fiber sound-absorbing cotton. Non-woven materials are the main raw materials for preparing fiber sound-absorbing cotton. In particular, short-fiber intercalated meltblown ultrafine fiber non-woven materials have excellent sound absorption characteristics due to their special structure. However, short-fiber intercalated meltblown sound-absorbing cotton has high porosity, loose structure, small fiber fineness, and large specific surface area, resulting in extremely poor waterproof performance. After absorbing water, the structure is easily damaged, it is prone to mildew, and the sound absorption performance is greatly reduced, leading to a poor service life. Summary of the Invention

[0004] The main objective of this invention is to provide a sound-absorbing material and its preparation method, aiming to solve the problem of poor service life of sound-absorbing materials.

[0005] To achieve the above objectives, the present invention provides a sound-absorbing material, comprising: The core layer comprises a composite material formed by sputtering ultrafine fibers intercalated with hollow elastic short fibers; The outer layer has two layers, which are respectively covered on opposite sides of the core layer. The outer layer includes flash-steamed nonwoven fabric, and the outer layer and the core layer form a three-layer structure.

[0006] In one embodiment, the meltblown microfiber comprises any one of polypropylene, polyester, and polylactic acid.

[0007] In one embodiment, the hollow elastic staple fiber includes any one of polyester hollow elastic staple fiber, polyamide staple fiber, and polylactic acid staple fiber.

[0008] In one embodiment, the content of the hollow elastic short fiber is 10% to 40% of the total weight of the composite material.

[0009] In one embodiment, the meltblown microfiber has a fiber diameter of 1 to 6 μm; and / or, The hollow elastic short fibers have a diameter of 16 to 30 μm and a length of 25 to 70 mm.

[0010] In one embodiment, the flash nonwoven fabric is made of polyethylene.

[0011] In one embodiment, the flash nonwoven fabric has an embossed structure formed on the outer side facing away from the core layer.

[0012] In one embodiment, the embossed structure is arranged in a rhombus shape, and the side length of the rhombus is 3 to 6 millimeters.

[0013] The present invention also provides a method for preparing a sound-absorbing material, for preparing the sound-absorbing material according to any one of claims 1 to 8, comprising: Composite materials are formed by intercalating ultrafine fibers into hollow elastic short fibers using meltblown spinning equipment. The sound-absorbing material is obtained by covering the upper and lower surfaces of the composite material with flash-evaporated nonwoven fabric and then hot-pressing the edges.

[0014] This invention provides a sound-absorbing material comprising a core layer and surface layers covering opposite sides of the core layer, forming a three-layer structure. Hollow elastic short fibers in the short-fiber intercalated meltblown nonwoven sound-absorbing cotton provide support within the meltblown filter cloth, effectively increasing the material's porosity. The fine meltblown fibers divide larger pores into smaller ones, increasing the surface area and giving it excellent sound absorption performance. The flash-evaporated nonwoven fabric and the short-fiber intercalated meltblown nonwoven sound-absorbing cotton are combined to form a sandwich-structured composite sound-absorbing material. Utilizing the waterproof and breathable properties of the flash-evaporated nonwoven fabric, as well as its good mechanical and protective properties, the performance defects of the short-fiber intercalated meltblown nonwoven sound-absorbing cotton are improved. This results in a sound-absorbing material with advantages such as waterproof and breathable properties, good sound absorption performance, high mechanical properties, and mildew resistance, thus improving the material's service life. Furthermore, due to the special structure of the flash-evaporated nonwoven fabric composite short-fiber intercalated meltblown nonwoven material, it also possesses good thermal insulation properties and can be used as a waterproof, breathable, and thermal insulation material in clothing, construction, automotive, and industrial fields. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the sound-absorbing material provided in the embodiment of the present invention.

[0016] Explanation of icon numbers: 100. Sound-absorbing material; 1. Surface layer; 2. Core layer.

[0017] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0020] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0021] Please see Figure 1 The present invention provides a sound-absorbing material, including a core layer 2 and a surface layer 1; the core layer 2 includes a composite material formed by sputtering ultrafine fiber intercalation into hollow elastic short fibers; the surface layer 1 has two layers, which are respectively covered on opposite sides of the core layer 2, and the surface layer 1 includes flash-spun nonwoven fabric, and the surface layer 1 and the core layer 2 form a three-layer structure.

[0022] This invention provides a sound-absorbing material comprising a core layer 2 and a surface layer 1 covering opposite sides of the core layer 2, forming a three-layer structure. Hollow elastic short fibers in the short-fiber intercalated meltblown nonwoven sound-absorbing cotton provide support within the meltblown filter cloth, effectively increasing the material's porosity. The fine meltblown fibers can divide larger pores into smaller pores, increasing the surface area and giving it excellent sound absorption performance. The flash-evaporated nonwoven fabric and the short-fiber intercalated meltblown nonwoven sound-absorbing cotton are combined to form a sandwich-structured composite sound-absorbing material. Utilizing the waterproof and breathable properties of the flash-evaporated nonwoven fabric, as well as its good mechanical and protective properties, the performance defects of the short-fiber intercalated meltblown nonwoven sound-absorbing cotton are improved. This results in a sound-absorbing material with advantages such as waterproof and breathable properties, good sound absorption performance, high mechanical properties, and mildew resistance, thus improving the material's service life. Furthermore, due to the special structure of the flash-evaporated nonwoven fabric composite short-fiber intercalated meltblown nonwoven material, it also possesses good thermal insulation properties and can be used as a waterproof, breathable, and thermal insulation material in clothing, construction, automotive, and industrial fields.

[0023] Furthermore, the materials used for the meltblown microfibers can be implemented in various ways. In this application, the meltblown microfibers include any one of polypropylene, polyester, and polylactic acid. In this embodiment, the meltblown microfibers need to be prepared by a meltblowing method. Any one of polypropylene, polyester, and polylactic acid is fed into a meltblown device to form microfibers. The resulting microfibers have good web-forming properties and are easy to meltblown.

[0024] Similarly, the hollow elastic short fiber material can be implemented in various ways. In this application, it includes any one of polyester hollow elastic short fiber, polyamide short fiber, and polylactic acid short fiber. In this embodiment, the hollow elastic short fiber plays a supporting role in the meltblown filter cloth, effectively improving the porosity of the material. The fine meltblown fiber can divide larger pores into smaller pores, increasing the surface area and giving it excellent sound absorption performance.

[0025] In the embodiments provided by the present invention, the meltblown microfiber can also be made of polyester material, and the fiber diameter can be selected in the range of 1 to 6 μm, such as 2 μm, 3 μm or 5 μm.

[0026] In addition, the content of the hollow elastic short fibers is 10% to 40% of the total weight of the composite material, such as 15%, 30%, or 35%, to ensure the supporting effect.

[0027] The diameter of the hollow elastic short fiber can be selected in the range of 16 to 30 μm, such as 18 μm, 25 μm or 28 μm, and the length can be selected in the range of 25 to 70 mm, such as 30 mm, 50 mm or 65 mm.

[0028] On the other hand, the material of the flash nonwoven fabric includes polyethylene.

[0029] The nonwoven fabric prepared by the polyethylene flash evaporation method has a thickness of 10 to 80 μm, a fiber diameter of 0.2 to 1 μm, and a pore size of 50 to 200 nm on the fabric surface.

[0030] Furthermore, the flash nonwoven fabric has an embossed structure formed on its outer side facing away from the core layer.

[0031] It should be noted that the embossing structure can be implemented in various ways, such as rectangular or linear patterns.

[0032] Furthermore, in this application, the embossed structure is arranged in a rhombus shape, with a side length of 3 to 6 millimeters. This is to improve the mechanical and protective properties of the flash-blown nonwoven fabric.

[0033] The present invention also provides a method for preparing a sound-absorbing material, comprising the following steps: S10. A composite material is formed by intercalating ultrafine fibers into hollow elastic short fibers using meltblown spinning equipment. In this process, the meltblown spinning head is connected to the exhaust port of the blower, the heating equipment is turned on, and the blower is started to raise the temperature at the spinning head to 100°C~200°C. While meltblowing ultrafine fibers, hollow elastic short fibers are simultaneously blown into the meltblown hot air flow, and after spinning and stretching, they are collected on the forming screen. S20. Apply flash-evaporated nonwoven fabric to the upper and lower surfaces of the composite material and seal the edges with hot pressing to obtain the sound-absorbing material.

[0034] Based on the above-mentioned sound-absorbing materials and their preparation methods, the present invention provides the following embodiments.

[0035] Example 1 Polyethylene flash-coated nonwoven fabric with its embossed side facing outwards is coated onto both sides of a meltblown microfiber intercalated hollow elastic short fiber composite nonwoven material. The polyethylene flash-coated nonwoven fabric is 20 μm thick; the meltblown fibers are polypropylene meltblown microfibers with an average diameter of 1.6 μm; the hollow elastic short fibers are polyester hollow elastic short fibers with an average diameter of 21 μm and an average length of 42 mm, with an addition amount of 20%. After hot-pressing and edge sealing, a meltblown microfiber composite flash-coated fabric sound-absorbing material is formed at 150℃. The composite sound-absorbing material has a sound absorption coefficient of up to 0.9; after water spraying and immersion tests, its water absorption rate is 0.52%; under a 5 kg load compression, the composite sound-absorbing cotton recovers rapidly within 3 seconds of load unloading; the mechanical strength of the sound-absorbing cotton is 257.6 N / 5 cm.

[0036] This embodiment provides a sound-absorbing material with a three-layer composite structure design, which has excellent sound absorption performance and mechanical strength.

[0037] The sound-absorbing material consists of two main parts: a core layer and a surface layer. The core layer is composed of a composite material formed by intercalating hollow elastic short fibers with melt-blown microfibers. The melt-blown microfibers are made of polypropylene and have a fiber diameter of 1.6 μm. These microfibers have excellent sound wave absorption capabilities and can effectively capture and dissipate sound energy.

[0038] The hollow elastic staple fiber is made of polyester hollow elastic staple fiber with a fiber diameter of 21μm and a length of 42mm, accounting for 20% of the total weight in the composite material. This hollow structure design increases the air layer inside the material, increases the complexity of the sound wave propagation path in the material, and at the same time, the elastic properties ensure that the material can quickly return to its original shape after being compressed.

[0039] The surface layer has two layers, which are respectively applied to opposite sides of the core layer to form a three-layer structure. The surface layer is made of polyethylene flash-spun nonwoven fabric with a thickness of 20μm.

[0040] The flash-spun nonwoven fabric has an embossed structure on its outer surface facing away from the core layer. The embossed structure is diamond-shaped with a side length of 4 mm. This embossed structure not only increases the aesthetics of the material surface, but more importantly, it increases the contact area between sound waves and the material surface, improving the sound wave scattering effect and thus enhancing the overall sound absorption performance.

[0041] The preparation process of this sound-absorbing material is as follows: Polyethylene flash-steamed nonwoven fabric with the embossed side facing outwards is applied to both sides of a meltblown microfiber intercalated hollow elastic short-fiber composite nonwoven material. Then, it undergoes hot-pressing consolidation and edge sealing treatment, with the hot-pressing temperature controlled at 150℃. The hot-pressing process ensures a strong bond between the three layers while maintaining the original properties of each layer.

[0042] Performance tests showed that the sound-absorbing material achieved a sound absorption coefficient of 0.9, demonstrating excellent sound absorption. In water spray and immersion tests, its water absorption rate was only 0.52%, indicating good waterproof performance. Under a 5kg load compression test, it quickly recovered within 3 seconds of load unloading, demonstrating excellent elastic recovery characteristics.

[0043] The material has a mechanical strength of 257.6 N / 5cm, which is sufficient to meet the needs of practical applications.

[0044] This three-layer composite structure design achieves an effective balance between sound absorption performance and mechanical properties. The composite fiber structure of the core layer provides the main sound absorption function, while the flash-evaporated nonwoven fabric on the surface not only protects the internal structure but also further enhances the sound absorption effect through embossing. The overall material maintains excellent sound absorption performance while possessing good waterproofness, elastic resilience, and mechanical strength.

[0045] This embodiment also provides a method for preparing a sound-absorbing material, as described in detail in Embodiment 1. The sound-absorbing material adopts a three-layer composite structure design, including a composite material core layer formed by sputtered ultrafine fiber intercalation with hollow elastic short fibers, and a flash-evaporated nonwoven fabric surface layer covering the opposite sides of the core layer.

[0046] The preparation method includes the following steps: Step 1: Preparation of composite materials.

[0047] Composite materials are formed by intercalating melt-blown ultrafine fibers into hollow elastic short fibers using meltblown spinning equipment. In this step, the meltblown spinning equipment first heats raw materials such as polypropylene to a molten state, and then stretches the molten polymer into ultrafine fibers through a high-speed airflow, with the fiber diameter controlled within the range of 1 to 6 μm.

[0048] Meanwhile, hollow elastic short fibers are evenly distributed in meltblown ultrafine fibers by intercalation, and the content of hollow elastic short fibers is controlled at 10% to 40% of the total weight of the composite material.

[0049] The process parameters of meltblown spinning equipment include melting temperature, airflow velocity, and receiving distance. Precise control of these parameters ensures the effective combination of microfiber and hollow elastic short fiber, forming a composite material structure with good sound absorption properties.

[0050] Step 2: Surface coating and hot-pressing edge sealing.

[0051] The sound-absorbing material is obtained by covering the upper and lower surfaces of the composite material with flash-evaporated nonwoven fabric and then hot-sealing the edges.

[0052] The specific operation is as follows: the embossed side of the polyethylene flash nonwoven fabric is placed outward and covered on the upper and lower surfaces of the composite material prepared in step one.

[0053] The flash nonwoven fabric has an embossed structure on the outer side facing away from the core layer. The embossed structure is arranged in a diamond shape with a side length of 3 to 6 millimeters.

[0054] Then, hot pressing and edge sealing are carried out. The hot pressing temperature is controlled at 150℃. The three-layer structure is firmly bonded through the hot pressing process. At the same time, the edges of the materials are sealed to prevent the internal fibers from falling off, ensuring the integrity and durability of the product.

[0055] Meltblown microfiber can be made of polyester material with a fiber diameter of 2μm. Different fiber diameters can be controlled by adjusting the process parameters of the meltblown spinning equipment.

[0056] Meltblown microfiber can also be made of polylactic acid material, and hollow elastic staple fiber is made of polylactic acid hollow elastic staple fiber with a fiber diameter of 25μm, a length of 50mm, and an addition amount of 30%. The thickness of flash nonwoven fabric is adjusted to 30μm.

[0057] The key to this preparation method lies in the precise control of the meltblown spinning equipment and the optimization of the hot-pressing process. During meltblown spinning, the high-speed airflow causes the ultrafine fibers to form a three-dimensional network structure, and the intercalation distribution of hollow elastic short fibers increases the elastic resilience of the material and the complexity of the sound wave propagation path.

[0058] The hot-press sealing process not only achieves an effective combination of the three-layer structure, but also, through the synergistic effect of temperature and pressure, enables each layer of material to maintain its original characteristics while forming a sound-absorbing material with excellent overall performance.

[0059] The sound-absorbing material prepared by this method has a sound absorption coefficient of 0.89 to 0.9 and a water absorption rate of only 0.52% to 0.65%. It can quickly recover within 3 seconds after unloading under a 5kg load compression, and its mechanical strength reaches 247.8 to 257.6 N / 5cm, which fully verifies the effectiveness of the preparation method and the excellent performance of the product.

[0060] Example 2 The embossed side of polyethylene flash nonwoven fabric is applied to both the top and bottom surfaces of meltblown microfiber intercalated hollow elastic short fiber composite nonwoven material. The polyethylene flash nonwoven fabric has a thickness of 30μm; the meltblown fiber is polylactic acid meltblown microfiber with an average fiber diameter of 2μm; the hollow elastic staple fiber is polylactic acid hollow elastic staple fiber with an average fiber diameter of 25μm and an average fiber length of 50mm, with an addition amount of 30%.

[0061] After hot pressing and edge sealing, meltblown microfiber composite flash cloth sound-absorbing material is formed, with a hot pressing temperature of 150℃.

[0062] The composite sound-absorbing material has a sound absorption coefficient of up to 0.89; after water spraying and immersion tests, its water absorption rate is 0.65%; the composite sound-absorbing cotton can quickly recover within 3 seconds after unloading under a 5kg load compression; the mechanical strength of the sound-absorbing cotton is 247.8 N / 5cm.

[0063] Comparative Example 1: A polyethylene film is coated on both sides of a meltblown microfiber intercalated hollow elastic short fiber composite nonwoven material. The polyethylene film is 20 μm thick. The meltblown fiber is polypropylene meltblown microfiber with an average fiber diameter of 1.6 μm. The hollow elastic short fiber is polyester hollow elastic short fiber with an average fiber diameter of 21 μm and an average fiber length of 42 mm, with an addition amount of 20%. The composite sound-absorbing material is then formed through hot pressing and edge sealing at 150℃. The sound absorption coefficient of the composite sound-absorbing material can reach 0.6; after water spraying and immersion tests, its water absorption rate is 0.3%; the composite sound-absorbing cotton is incompressible; the mechanical strength of the sound-absorbing cotton is 140.3 N / 5cm.

[0064] Comparative Example 2: This is a nonwoven material composed of meltblown microfiber intercalated with hollow elastic short fibers, with no covering on either the upper or lower surface. The meltblown fibers are polypropylene meltblown microfibers with an average diameter of 1.6 μm; the hollow elastic short fibers are polyester hollow elastic short fibers with an average diameter of 21 μm and an average length of 42 mm, with an addition amount of 20%. The sound-absorbing material has a sound absorption coefficient of up to 0.75; after water spraying and immersion tests, its water absorption rate is 60%; under a 5 kg load compression, the sound-absorbing cotton recovers rapidly within 3 seconds after unloading; the mechanical strength of the sound-absorbing cotton is 61.8 N / 5 cm.

[0065] In the embodiments and comparative examples provided in this invention, the performance of different samples is compared. In Example 1, the sound absorption is excellent, it is compressible, has low water absorption, and excellent mechanical properties; in Comparative Example 1, the sound absorption is poor, it is incompressible, has low water absorption, and moderate mechanical properties; in Comparative Example 2, the sound absorption is moderate, it is compressible, has high water absorption, and poor mechanical properties.

[0066] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A sound absorbing material, characterized by, include: The core layer comprises a composite material formed by sputtering ultrafine fibers intercalated with hollow elastic short fibers; The outer layer has two layers, which are respectively covered on opposite sides of the core layer. The outer layer includes flash-steamed nonwoven fabric, and the outer layer and the core layer form a three-layer structure.

2. The sound-absorbing material according to claim 1, characterized in that, The meltblown microfiber includes any one of polypropylene, polyester, and polylactic acid.

3. The sound-absorbing material according to claim 1, characterized in that, The diameter of the melt-blown microfiber is 1 to 6 μm.

4. The sound-absorbing material according to claim 1, characterized in that, The hollow elastic staple fiber includes any one of polyester hollow elastic staple fiber, polyamide staple fiber, and polylactic acid staple fiber.

5. The sound-absorbing material according to claim 1, characterized in that, The content of the hollow elastic short fiber is 10% to 40% of the total weight of the composite material; and / or, The hollow elastic short fibers have a diameter of 16 to 30 μm and a length of 25 to 70 mm.

6. The sound-absorbing material according to claim 1, characterized in that, The material of the flash-steamed nonwoven fabric includes polyethylene.

7. The sound-absorbing material according to claim 1, characterized in that, The flash nonwoven fabric has an embossed structure on its outer side facing away from the core layer.

8. The sound-absorbing material according to claim 7, characterized in that, The embossed structure is arranged in a rhombus shape, and the side length of the rhombus is 3 to 6 millimeters.

9. A method for preparing a sound-absorbing material, used to prepare the sound-absorbing material according to any one of claims 1 to 8, characterized in that, include: Composite materials are formed by intercalating ultrafine fibers into hollow elastic short fibers using meltblown spinning equipment. The sound-absorbing material is obtained by covering the upper and lower surfaces of the composite material with flash-evaporated nonwoven fabric and then hot-pressing the edges.

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