Soundproofing / absorbing fibrous material and method for its production

Abstract

This invention belongs to the field of fiber composite materials technology, specifically relating to a sound-insulating / sound-absorbing fiber material and its preparation method. This sound-insulating / sound-absorbing fiber material is a core-sheath structure fiber composite material in which EPD and / or HDPE, as well as PEER and / or PPI, are added, increasing the specific strength of its single fiber from 2.5 cN / dtex without the addition of EPD, HDPE, PEER, and PPI to 3 cN / dtex–7 cN / dtex. Simultaneously, the sound insulation of the fiber felt prepared based on this sound-insulating / sound-absorbing fiber material is increased by 1.0 dB–4.2 dB compared to the fiber felt without the addition of EPD, HDPE, PEER, and PPI.

Description

Technical Field

[0001] This invention belongs to the field of fiber composite materials technology, specifically relating to a sound-insulating / sound-absorbing fiber material and its preparation method. Background Technology

[0002] Fiber felts are widely used in building sound insulation, automotive interiors, industrial filtration, and protective materials due to their advantages such as light weight, porosity, and good flexibility. Fiber felts are typically made by interlacing a large number of fibers (including composite single fibers) through processes such as web laying, needle punching, or thermal bonding. Their macroscopic properties (such as mechanical strength and sound insulation ability) largely depend on the properties of the individual fibers that make up the fiber felt.

[0003] However, conventional monofibers have low specific strength, making fiber felts difficult to meet the demands of high-intensity applications. Furthermore, fiber felts have limited sound insulation performance, especially in the low-frequency range. To improve sound insulation, existing technologies often require increasing the weight or thickness of the fiber felt, but this leads to increased material costs and construction difficulties, hindering lightweight applications.

[0004] Therefore, developing a composite fiber material that can simultaneously improve strength and sound insulation performance is of great significance for the preparation of fiber felt. Summary of the Invention

[0005] Based on this, the present invention provides a sound insulation / sound absorption fiber material and its preparation method, aiming to achieve both high specific strength and excellent sound insulation performance in the sound insulation / sound absorption fiber material through reasonable component design, without significant change in weight.

[0006] To achieve the above objectives, the present invention can adopt the following technical solutions: This invention provides a sound-insulating / sound-absorbing fiber material, comprising a core layer and a sheath layer. The core layer comprises PET and a core layer polymer. The PET has a melting point of 250℃-260℃ and an intrinsic viscosity of 0.68 dL / g-0.80 dL / g. The core layer polymer is selected from PEER and / or PPI. The sheath layer comprises COPET and a sheath polymer. The COPET has a melting point of 230℃-240℃ and an intrinsic viscosity of 0.64 dL / g-0.68 dL / g. The sheath polymer is selected from EPD and / or HDPE. The intrinsic viscosity of PET is greater than that of COPET.

[0007] Preferably, in the above-mentioned sound insulation / sound absorption fiber material, the mass of the core layer polymer is 1%-50% of the core layer mass; and the mass of the sheath layer polymer is 1-10% of the sheath layer mass.

[0008] More preferably, in the above-mentioned sound insulation / sound absorption fiber material, the mass of the core layer polymer is 25% of the core layer mass; and the mass of the sheath layer polymer is 5% of the sheath layer mass.

[0009] More preferably, in the above sound insulation / sound absorption fiber material, the core polymer is selected from PEER and PPI, and the mass ratio of PEER to PPI is (1-9):(1-9); the sheath polymer is selected from EPD and HDPE, and the mass ratio of EPD to HDPE is (1-9):(1-9).

[0010] More preferably, in the above-mentioned sound insulation / sound absorption fiber material, the core layer polymer is selected from PEER and PPI, and the mass ratio of PEER and PPI is 1:1; the sheath polymer is selected from EPD and HDPE, and the mass ratio of EPD and HDPE is 1:1.

[0011] Preferably, in the above-mentioned sound insulation / sound absorption fiber material, the mass of the sheath layer is 10%-50% of the total mass of the core layer and the sheath layer.

[0012] More preferably, in the above-mentioned sound insulation / sound absorption fiber material, the mass of the sheath layer is 30% of the total mass of the core layer and the sheath layer.

[0013] Another aspect of the present invention provides a method for preparing the above-mentioned sound-insulating / sound-absorbing fiber material, the method comprising: (1) The molten sheath and core are fed into a coaxial electrospinning machine for spinning to obtain a composite fiber with sheath covering the core. The spinning temperature is 270℃-300℃. (2) The composite fiber with sheath covering core layer is cooled and molded at 120℃-140℃ to obtain sound insulation / sound absorption fiber material.

[0014] In another aspect, the present invention provides a fiber felt, which is prepared from the sound-insulating / sound-absorbing fiber material of the present invention. The fiber felt has a thickness of 2mm-4mm and a basis weight of 800g / m³. 2 -2000g / m 2 .

[0015] In another aspect, the present invention provides a method for preparing fiber felt, the method comprising: (1) Lay the sound insulation / sound absorption fiber material into a web and spunbond it to obtain the base fabric; (2) The base fabric is cross-laid at 45° to obtain an overlapping base fabric; (3) The overlapping base fabric is needle-punched and entangled at least once to obtain a fiber felt semi-finished product; (4) The fiber felt semi-finished product is steam-formed to obtain fiber felt.

[0016] in, (i) The steam forming process is performed at a pressure of 14-17 Bar; and / or (ii) Based on (i), the steam forming process time is 13s-20s; and / or (iii) The temperature of the steam forming process is 200℃-210℃.

[0017] The beneficial effects of this invention include at least the following: The sound-insulating / sound-absorbing fiber material provided by this invention is a fiber composite material with a core-sheath structure in which EPD (ethylene propylene diene monomer) and / or HDPE (high-density polyethylene) and PEER (polymer-reinforced elastic material, also known as TPEE) and / or PPI (polypropyleneimide) are added, which increases the specific strength of its single fiber from 2.5 cN / dtex without the addition of EPD, HDPE, PEER and PPI to 3 cN / dtex-7 cN / dtex; at the same time, the sound insulation of the fiber felt prepared based on this sound-insulating / sound-absorbing fiber material is increased by 1.0 dB-4.2 dB compared with the fiber felt without the addition of EPD, HDPE, PEER and PPI; and the weight does not change significantly. Detailed Implementation

[0018] The embodiments described are provided to better illustrate the present invention, but are not intended to limit the scope of the invention to the embodiments described. Therefore, non-essential improvements and adjustments made to the embodiments by those skilled in the art based on the above description are still within the scope of protection of the present invention.

[0019] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. Singular expressions include plural expressions unless they have a distinct meaning in the context. As used herein, it should be understood that terms such as “comprising,” “having,” “including,” are intended to indicate the presence of features, numbers, operations, components, parts, elements, materials, or combinations thereof. The terminology of the invention is disclosed in the specification and is not intended to exclude the possibility that one or more other features, numbers, operations, components, parts, elements, materials, or combinations thereof may be present or added. As used herein, “ / ” may be interpreted as “and” or “or,” depending on the context.

[0020] In a first aspect, embodiments of the present invention provide a sound-insulating / sound-absorbing fiber material, comprising a core layer and a sheath layer. The core layer comprises PET and a core layer polymer. The PET has a melting point of 250°C-260°C and an intrinsic viscosity of 0.68 dL / g-0.80 dL / g. The core layer polymer is selected from PEER and / or PPI. The sheath layer comprises COPET and a sheath polymer. The COPET has a melting point of 230°C-240°C and an intrinsic viscosity of 0.64 dL / g-0.68 dL / g. The sheath polymer is selected from EPD and / or HDPE. The intrinsic viscosity of PET is greater than that of COPET.

[0021] It should be noted that PET is a high-melting-point, high-viscosity matrix resin, and specifications with melting points of 253℃, 255℃, and 258℃ can be selected, corresponding to intrinsic viscosities of 0.71dL / g, 0.74dL / g, and 0.77dL / g, respectively. It exhibits strong structural rigidity and excellent mechanical strength. PEER and PPI possess excellent damping energy dissipation and high-frequency sound absorption properties, working together to construct a high-strength support framework for the core layer. COPET uses a lower melting point and lower viscosity system, with melting points of 233℃, 235℃, and 238℃, and an intrinsic viscosity of 0.6. With concentrations of 5 dL / g, 0.66 dL / g, and 0.67 dL / g, these materials are compatible with the sheath-modified polymers for melt spinning. EPD exhibits excellent elasticity and outstanding damping performance, while HDPE provides stable molding and resistance to temperature and weathering. Together, they improve the flexible coating effect of the sheath layer. The overall setting of PET viscosity is higher than that of COPET, ensuring high melt strength in the core layer and preventing fiber breakage. The sheath layer melt has good fluidity and is easy to coat evenly, forming a stable core-skin profile structure. By relying on multi-layer interface impedance and damping friction loss of sound wave energy, the overall sound insulation and absorption performance is improved from the material's basic structural level.

[0022] In some specific examples, in the above-mentioned sound insulation / sound absorption fiber materials, the mass of the core layer polymer is 1%-50% of the core layer mass; and the mass of the sheath layer polymer is 1-10% of the sheath layer mass.

[0023] It should be noted that the polymer doping ratio of the core layer can be selected as 12%, 25%, or 38%, and the polymer doping ratio of the sheath layer can be selected as 3%, 5%, or 7%. Low doping of the sheath layer modifier can optimize the surface elasticity and fiber flexibility, avoiding excessive addition that would cause melt viscosity disorder and increased spinning breakage. The core layer adopts a wide range of doping design, which can adjust the overall damping coefficient and structural rigidity as needed. If the ratio is too low, the damping and sound absorption will be insufficient, and if the ratio is too high, the strength and thermal stability of the core layer skeleton will be reduced. This ratio range takes into account the stability of molding and processing, the mechanical basis of the fiber, and the sound wave damping attenuation capability, and is suitable for the noise attenuation control requirements of different frequency bands.

[0024] In some specific examples, in the above-mentioned sound insulation / sound absorption fiber materials, the mass of the core layer polymer is 25% of the core layer mass; and the mass of the sheath layer polymer is 5% of the sheath layer mass.

[0025] It should be noted that a fixed 25% core layer modified polymer can maximize the energy dissipation advantages of PEER and PPI composite damping while ensuring that the high-strength skeleton of the PET matrix is ​​not weakened, and stably dissipate the energy of mid-to-high frequency sound wave vibration. A fixed 5% sheath layer modified addition is the optimal balance point, which can rely on EPD and HDPE to synergistically improve the softness of the sheath layer and the fiber crimping and interweaving ability, without causing abnormal melt rheological properties. It has good batch spinning uniformity and high regularity of the core-sheath structure, and comprehensively balances the material's mechanical properties, processing adaptability and basic sound absorption and insulation effects.

[0026] In some specific examples, in the above sound insulation / sound absorption fiber materials, the core polymer is selected from PEER and PPI, with a mass ratio of PEER to PPI of (1-9):(1-9); the sheath polymer is selected from EPD and HDPE, with a mass ratio of EPD to HDPE of (1-9):(1-9).

[0027] It should be noted that the PEER and PPI compound system can be selected with intermediate ratios of 2:7, 4:5, and 6:3, relying on the complementary damping temperature ranges of the two resins to broaden the effective sound absorption temperature range of the material; the EPD and HDPE compound system can be selected with intermediate ratios of 3:6, 5:4, and 7:2. EPD provides high elasticity and viscoelastic damping, while HDPE provides advantages such as dimensional stability, temperature resistance, and deformation resistance. The two-way compound system has a wide adjustable range, and the component ratio can be flexibly adjusted according to low-frequency, mid-frequency, and high-frequency noise control scenarios to improve the energy dissipation of fiber interface friction and the sound insulation and barrier effect of the overall structure.

[0028] In some specific examples, in the above sound insulation / sound absorption fiber materials, the core polymer is selected from PEER and PPI, with a mass ratio of PEER to PPI of 1:1; the sheath polymer is selected from EPD and HDPE, with a mass ratio of EPD to HDPE of 1:1.

[0029] It should be noted that the equal proportion of PEER and PPI can achieve balanced and synergistic damping performance, without the performance bias caused by an excessively high proportion of a single component, ensuring that the core layer always has stable sound wave attenuation efficiency under normal ambient temperature; the equal proportion of EPD and HDPE takes into account both elastic flexibility support and rigid dimensional stability, optimizes the surface smoothness of individual core and sheath fibers and the interwoven stacked pore structure, allowing sound waves to be refracted and dissipated by friction multiple times in the fiber pores, while improving the overall compression resistance and fatigue resistance of the fiber, making the structure less prone to collapse after molding, and maintaining stable sound insulation and sound absorption performance over a long period of time.

[0030] In some specific examples, the mass of the sheath layer in the above-mentioned sound insulation / sound absorption fiber materials is 10%-50% of the total mass of the core layer and the sheath layer.

[0031] It should be noted that in this invention, if there is too little or too much COPET, the tensile strength, tear strength, and sound absorption coefficient will all decrease. Specifically, if too little sheath is added, the final felt will have poor formability and the tensile strength will drop sharply. Therefore, the mass of the sheath layer in this invention can be further preferably 10%-50% of the total mass of the core layer and sheath layer, such as 15%, 20%, 25%, 30%, 35%, 40%, or 45%, etc., that is, the mass ratio of the core layer to the sheath layer can be 9:1, 8:2, 7:3, 6:4, or 5:5, etc.

[0032] In some specific examples, the mass of the sheath layer in the aforementioned sound insulation / sound absorption fiber material is 30% of the total mass of the core layer and the sheath layer.

[0033] It should be noted that the mass of the sheath layer in this invention can be further preferably 30% of the total mass of the core layer and the sheath layer, that is, the mass ratio of the sheath layer to the core layer is 7:3. The performance of the fiber composite material prepared under this ratio is better than that under other ratios.

[0034] Secondly, embodiments of the present invention provide a method for preparing the above-mentioned sound-insulating / sound-absorbing fiber material, the method comprising: (1) The molten sheath and core are fed into a coaxial electrospinning machine for spinning to obtain a composite fiber with sheath covering the core. The spinning temperature is 270℃-300℃. (2) The composite fiber with sheath covering core layer is cooled and molded at 120℃-140℃ to obtain sound insulation / sound absorption fiber material.

[0035] It should be noted that, during the preparation of the sound-insulating / sound-absorbing fiber material in this invention, the coaxial electrospinning technology can precisely control the uniformity of the coating between the sheath layer and the core layer, avoiding the interlayer separation problem that occurs in traditional composite processes. This method is suitable for preparing high-strength, multifunctional fiber composite materials and can be widely used in filter materials, biomedical scaffolds, smart textiles, and other fields, while also offering the advantages of simple processing and scalable production. Furthermore, the key process parameters of the coaxial electrospinning machine can be flexibly adjusted according to the viscosity and surface tension of the sheath and core layer materials to further optimize the coating effect and morphology of the composite fibers. The above parameter ranges are within the industry's standard range, ensuring the stability of the spinning process.

[0036] Thirdly, embodiments of the present invention provide a fiber felt, which is made of the sound-insulating / sound-absorbing fiber material of the present invention. The fiber felt has a thickness of 2mm-4mm and a basis weight of 800g / m³. 2 -2000g / m 2 .

[0037] The actual forming thickness of the fiber felt can be 2.3mm, 2.9mm, or 3.5mm, and the corresponding areal density can be selected as 950g / m². 2 1300g / m 2 1750g / m 2 The moderate thickness ensures the formation of a multi-level microporous tortuous structure inside, which is conducive to the repeated friction and attenuation of sound waves; the reasonable weight range takes into account the balance between the sound insulation effect of surface density and the sound absorption effect of breathability. If the weight is too low, the barrier is thin and the low-frequency sound insulation is poor. If the weight is too high, it will be dense and compacted, and the porosity will decrease, which will weaken the sound absorption capacity. This parameter system is perfectly adapted to conventional noise reduction scenarios such as automotive interiors and building partitions. The structure is fluffy and uniform, and the overall acoustic performance is balanced and stable.

[0038] Fourthly, embodiments of the present invention provide a method for preparing fiber felt, the method comprising: (1) Lay the sound insulation / sound absorption fiber material into a web and spunbond it to obtain the base fabric; (2) The base fabric is cross-laid at 45° to obtain an overlapping base fabric; (3) The overlapping base fabric is needle-punched and entangled at least once to obtain a fiber felt semi-finished product; (4) The fiber felt semi-finished product is steam-formed to obtain fiber felt.

[0039] in, (i) The steam forming process is performed at a pressure of 14-17 Bar; and / or (ii) Based on (i), the steam forming process time is 13s-20s; and / or (iii) The temperature of the steam forming process is 200℃-210℃.

[0040] It should be noted that the steam setting pressure can be selected as 14.8 Bar, 15.5 Bar, or 16.2 Bar, the processing time can be selected as 15s, 17s, or 19s, and the setting temperature can be selected as 202℃, 205℃, or 208℃. The 45° cross-laying can achieve uniform mechanical properties in all directions, eliminating the drawback of weak strength in one direction. The needle-punched entanglement strengthens the interwoven fiber nodes, improving the overall integrity and resistance to loosening. The medium-pressure short-time high-temperature steam action can gently melt the trace components on the surface to achieve node bonding and setting, which does not damage the original porous sound-absorbing pore structure, and significantly improves the dimensional stability, anti-settling and anti-flattening ability of the fiber felt. It accurately solidifies the multi-layer damping sound insulation system, and the finished product has high flatness, weather resistance and durability, and the sound insulation and sound absorption indicators have a small attenuation under long-term service. In addition, in this invention, if the steam pressure is less than 14 Bar, it cannot be formed and the tensile strength is greatly reduced; in addition, the steam time is 13s-20s, which is too short to form and too long to form the product, which greatly reduces the acoustic effect; furthermore, the steam temperature is 200℃-210℃, which is too high to carbonize the fibers and make them brittle, and too low to form.

[0041] To better understand the present invention, specific examples are provided below to further illustrate the content of the present invention, but the content of the present invention is not limited to the examples below.

[0042] Preparation Examples The preparation methods of PET and COPET used in this embodiment and comparative example are not limited. Existing technologies can be used as long as the melting point and intrinsic viscosity requirements are met, such as existing technologies CN105077898B, CN113308802A, CN113403755A, and CN113417029B.

[0043] In the embodiments and comparative examples of this invention, EPD (EPDM) is Sinopec Mitsui, 2032PM; HDPE is Daqing Petrochemical, 50008; PEER (TPEE) is Baoruilong, 7145D; and PPI is Zhongyuan Petrochemical, PPH-Y25.

[0044] Example 1 (1) Melting the sheath material: Mix COPET and EPD, with EPD added at 5% of the mass of the sheath material, and the melting temperature is 240℃; COPET has a melting point of 240℃ and an intrinsic viscosity of 0.65dL / g; The core layer material is melted: PET and PEER are mixed, COPET is melted, the amount of PEER added is 25% of the mass of the core layer material, and the melting temperature is 260℃; the melting point of PET is 260℃, and the intrinsic viscosity of PET is 0.68dL / g; The mass ratio of core material to sheath material is 7:3.

[0045] (2) The molten sheath material and core material were fed into a coaxial electrospinning machine for spinning to obtain composite fibers. The spinning temperature was 280℃. The electrospinning parameters were set as follows: metal nozzle diameter: shell layer 1.06mm, core layer 0.24mm; distance between copper receiving plate and nozzle 10cm; voltage 10kV; microsyringe push speed: shell layer 0.17mL / h, core layer 0.7mL / h. (3) The composite fiber was cooled and molded at 130°C. The average fineness of the cooled and molded composite fiber was 3.8D and the basis weight was 162g / m². 2 ; (4) The cooled composite fibers are laid into a web, and then spunbonded into a base fabric; then the base fabric is laid into an overlapping web at a 45° angle. (5) The overlapping base fabric is subjected to a first needle entanglement and a second needle entanglement to obtain a fiber felt semi-finished product; (6) Cut the semi-finished fiber felt into 10cm×10cm sizes, and steam-form the cut fiber felt to obtain the finished fiber felt; wherein, the steam pressure is 15 Bar, the steam time is 15s, and the steam temperature is 200℃; the basis weight of the finished fiber felt is 1205g / m³. 2 The thickness is 2.02mm.

[0046] Example 2 Example 2 is largely the same as Example 1, except that HDPE is used instead of EPD in the sheath material of Example 2. Otherwise, the same as in Example 1, and fiber mat is prepared. The composite fiber after cooling and molding has an average fineness of 3.8D and a basis weight of 161 g / m². 2 The finished fiber felt has a basis weight of 1203 g / m². 2 The thickness is 2.02mm.

[0047] Example 3 Example 3 is largely the same as Example 1, except that PPI is used instead of PEER in the core layer material of Example 3. Otherwise, the same as in Example 1, and a fiber felt is prepared. The composite fiber after cooling and molding has an average fineness of 3.8D and a basis weight of 162 g / m². 2 The finished fiber felt has a basis weight of 1205 g / m². 2 The thickness is 2.01mm.

[0048] Example 4 Example 4 is largely the same as Example 1, except that HDPE is used instead of EPD and PPI is used instead of PEER in the sheath material of Example 4. The fiber mat is prepared in the same manner as in Example 1. The average fineness of the composite fiber after cooling and molding is 3.8D, and the basis weight is 162 g / m². 2 The finished fiber felt has a basis weight of 1205 g / m². 2 The thickness is 2.02mm.

[0049] Example 5 Example 5 is largely the same as Example 1, except that HDPE and EPD are added in equal amounts when the sheath material is melted in Example 5. The total amount of EPD and HDPE added is 5% of the mass of the sheath material. Otherwise, it is the same as Example 1, and a fiber felt is prepared. The average fineness of the composite fiber after cooling and molding is 3.7D, and the basis weight is 163 g / m². 2 The finished fiber felt has a basis weight of 1208 g / m². 2 The thickness is 2.03mm.

[0050] Example 6 Example 6 is largely the same as Example 1, except that PPI is added during the melting of the core layer raw material in Example 6. The amounts of PPI and PEER are equal, and the total amount of PEER and PPI added is 25% of the mass of the core layer raw material. Otherwise, it is the same as Example 1, and a fiber felt is prepared. The average fineness of the composite fiber after cooling and molding is 3.7D, and the basis weight is 163 g / m². 2 The finished fiber felt has a basis weight of 1208 g / m². 2 The thickness is 2.03mm.

[0051] Example 7 Example 7 is largely the same as Example 1, except that when the sheath material in Example 7 is melted, HDPE and EPD are added in equal amounts, with the total amount of EPD and HDPE being 5% of the sheath material's mass; when the core material is melted, PPI and PEER are added in equal amounts, with the total amount of PEER and PPI being 25% of the core material's mass. Other steps are the same as in Example 1, and a fiber felt is prepared. The average fineness of the composite fiber after cooling and molding is 3.7D, and its basis weight is 164 g / m². 2 The finished fiber felt has a basis weight of 1210 g / m². 2 The thickness is 2.04mm.

[0052] Examples 8 to 9 Examples 8 and 9 are largely the same as Example 7, except for the total amount of EPD and HDPE added, and the total amount of PEER and PPI added. Otherwise, they are the same as Example 7, resulting in different fiber mats. The total amounts of EPD and HDPE added, and the total amounts of PEER and PPI added, are shown below: Example 8: The total amount of EPD and HDPE added was 1% of the sheath material mass, and the total amount of PEER and PPI added was 50% of the core material mass; wherein, the average fineness of the composite fiber after cooling and molding was 3.6D, and the basis weight was 168g / m². 2 The finished fiber felt has a basis weight of 1220 g / m². 2 The thickness is 2.12mm; Example 9: The total amount of EPD and HDPE added is 10% of the sheath material mass, and the total amount of PEER and PPI added is 1% of the core material mass; wherein, the average fineness of the composite fiber after cooling and molding is 3.8D, and the basis weight is 162g / m². 2 The finished fiber felt has a basis weight of 1205 g / m². 2 The thickness is 2.02mm.

[0053] Comparative Example 1 Comparative Example 1 is largely the same as Example 1, except that EPD and PEER are not added in Comparative Example 1. Otherwise, the same as in Example 1, a fiber felt is prepared. The composite fiber after cooling and molding has an average fineness of 4D and a basis weight of 159 g / m². 2 The finished fiber felt has a basis weight of 1200g / m². 2 The thickness is 2mm.

[0054] Performance testing (a) Single fiber specific strength test According to GB / T 14337-2022, the single fiber specific strength of the composite fibers prepared in step (3) of the examples and comparative examples after cooling and molding was tested respectively, and the results are shown in Table 1 below.

[0055] Table 1. Single fiber specific strength test results As can be seen from Table 1 above, the specific strength of the single fiber of the composite fiber prepared by cooling and molding in Examples 1 to 9 is significantly higher than that of Comparative Example 1. Among them, the specific strength of Example 7 is the highest, reaching 6.7 cN / dtex, which is about 168% higher than that of Comparative Example 1 (2.5 cN / dtex).

[0056] In addition, comparing Examples 1 to 4 with Comparative Example 1, it can be seen that adding EPD, HDPE, PEER, and PPI individually can improve the specific strength, but the improvement is limited (+(1.1-1.3)), and the differences between different combinations are not significant.

[0057] Furthermore, comparing Example 5 with Examples 1 and 2 reveals that the specific strength of Example 5 is significantly higher than either of them (4.8 > 3.8 and > 3.6), and even higher than the average value of both (3.7). This indicates that EPD and HDPE have a synergistic reinforcing effect in the sheath.

[0058] Furthermore, comparing Example 5 with Examples 1 and 3 reveals that the specific strength of Example 5 is significantly higher than either of them (5.0 > 3.8 and > 3.7), and also higher than their average value (3.75). This indicates that PEER and PPI have a synergistic reinforcing effect in the core layer.

[0059] Furthermore, comparing Example 7 with Examples 5 and 6 reveals that the specific strength of Example 6 is not only higher than both of them, but also higher than half the sum of the two (4.9), and exhibits the greatest improvement. This demonstrates that sheath synergy and core synergy can be superimposed, producing a stronger dual synergistic effect.

[0060] (II) Sound insulation (sound transmission loss) test According to the test examples of GB / T 45305.2-2025 and the sound insulation of fiber felts prepared in different frequency bands (400Hz, 1000Hz, 2000Hz, 2500Hz, 2500Hz, 8000Hz and 8000Hz) in comparative examples, and the Rw values ​​of each group were calculated according to GB / T 50121-2005, the results are shown in Table 2 below.

[0061] Table 2. Sound Insulation (Sound Transmission Loss) Test Results As can be seen from Table 2 above, the sound insulation of the fiber felts prepared in Examples 1 to 9 is significantly better than that of Comparative Example 1 at different frequencies. Among them, the fiber felt prepared in Example 7 has the best sound insulation performance.

[0062] In addition, comparing Examples 1 to 4 with the comparative examples, it can be seen that adding EPD, HDPE, PEER, and PPI individually can all improve the sound insulation, but the improvement is limited. EPD is slightly better than HDPE, while PEER and PPI have similar effects.

[0063] Furthermore, comparing Example 5 with Examples 1 and 2 reveals that the ΔR of Example 5 is significantly higher than either of the other two, and also higher than their average value. This indicates that EPD and HDPE have a synergistic sound insulation enhancement effect within the sheath layer.

[0064] Furthermore, comparing Example 6 with Examples 1 and 3 reveals that the ΔR of Example 6 is significantly higher than either of the other two, and also higher than the average value. This indicates that PEER and PPI have a synergistic effect in enhancing sound insulation within the core layer.

[0065] Furthermore, comparing Example 7 with Examples 5 and 6 reveals that the ΔR of Example 7 is not only higher than both of them, but also higher than half the sum of the two, and exhibits the greatest improvement. This indicates that sheath synergy and core synergy can be superimposed, producing a stronger dual synergistic effect and achieving the best sound insulation performance.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A sound-insulating / sound-absorbing fiber material, comprising a core layer and a sheath layer, characterized in that, The core layer comprises PET and a core layer polymer. The PET has a melting point of 250℃-260℃ and an intrinsic viscosity of 0.68dL / g-0.80dL / g. The core layer polymer is selected from PEER and / or PPI. The sheath comprises COPET and a sheath polymer; the melting point of COPET is 230℃-240℃, and the intrinsic viscosity of COPET is 0.64dL / g-0.68dL / g; the sheath polymer is selected from EPD and / or HDPE. The intrinsic viscosity of PET is greater than that of COPET.

2. The sound-insulating / sound-absorbing fiber material according to claim 1, characterized in that, The mass of the core layer polymer is 1%-50% of the core layer mass; The mass of the sheath polymer is 1-10% of the sheath mass.

3. The sound insulation / sound absorption fiber material according to claim 2, characterized in that... The mass of the core layer polymer is 25% of the core layer mass; The mass of the sheath polymer is 5% of the sheath mass.

4. The sound-insulating / sound-absorbing fiber material according to any one of claims 1 to 3, characterized in that, The core polymer is selected from PEER and PPI, and the mass ratio of PEER to PPI is (1-9):(1-9). The sheath polymer is selected from EPD and HDPE, with a mass ratio of EPD to HDPE of (1-9):(1-9).

5. The sound-insulating / sound-absorbing fiber material according to claim 4, characterized in that, The core polymer is selected from PEER and PPI, with a mass ratio of PEER to PPI of 1:

1. The sheath polymer is selected from EPD and HDPE, with a mass ratio of EPD to HDPE of 1:

1.

6. The sound-insulating / sound-absorbing fiber material according to claim 1, 2, 3 or 5, characterized in that, The mass of the sheath is 10%-50% of the total mass of the core and sheath.

7. The sound-insulating / sound-absorbing fiber material according to claim 6, characterized in that, The mass of the sheath is 30% of the total mass of the core and sheath.

8. A method for preparing the sound-insulating / sound-absorbing fiber material according to any one of claims 1 to 7, characterized in that, Preparation methods include: (1) The molten sheath and core are fed into a coaxial electrospinning machine for spinning to obtain a composite fiber with sheath covering the core. The spinning temperature is 270℃-300℃. (2) The composite fiber with sheath covering core layer is cooled and molded at 120℃-140℃ to obtain sound insulation / sound absorption fiber material.

9. A fiber felt, characterized in that, The soundproofing / absorbing fibrous material according to any one of claims 1 to 7, wherein the fibrous mat has a thickness of 2 mm to 4 mm and a grammage of 800 g / m 2 - 2000 g / m 2 .

10. The method for preparing the fiber felt according to claim 9, characterized in that, Preparation methods include: (1) Lay the sound insulation / sound absorption fiber material into a web and spunbond it to obtain the base fabric; (2) The base fabric is cross-laid at 45° to obtain an overlapping base fabric; (3) The overlapping base fabric is needle-punched and entangled at least once to obtain a fiber felt semi-finished product; (4) The fiber felt semi-finished product is steam-formed to obtain fiber felt. in, (i) The steam forming process is performed at a pressure of 14-17 Bar; and / or (ii) Based on (i), the steam forming process time is 13s-20s; and / or (iii) The temperature of the steam forming process is 200℃-210℃.

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