Flame-retardant natural bamboo fiber acoustic board as well as preparation method and application thereof

Abstract

The invention relates to the technical field of indoor decoration, in particular to a flame-retardant natural bamboo fiber acoustic board and a preparation method and application thereof. 4080 polyester fibers and conventional polyester fibers are mixed and then sequentially subjected to opening, carding, cross lapping and needling, and polyester non-woven fabric is obtained; 4080 polyester fibers and natural bamboo fibers are mixed and then sequentially subjected to opening, carding, cross lapping and needling, and a natural bamboo fiber composite felt is obtained; polyester non-woven fabrics are placed on the upper surface and the lower surface of the natural bamboo fiber composite felt and then sequentially subjected to needling, hot melting and cooling, and the flame-retardant natural bamboo fiber acoustical board is obtained. The sound-absorbing board is produced by using the natural bamboo fibers with lower fineness, so that a better low-frequency sound-absorbing effect is realized, and the problem of poor low-frequency sound-absorbing effect of the traditional fiber composite material sound-absorbing board is solved; and through dipping flame-retardant modification on the natural bamboo fibers, a better flame-retardant effect and lower heat release are simply and efficiently achieved.

Description

Technical Field

[0001] This invention relates to the field of interior decoration technology, and in particular to a flame-retardant bamboo fiber sound-absorbing board, its preparation method, and its application. Background Technology

[0002] Concepts such as energy conservation, emission reduction, and environmental protection have permeated all walks of life. In the field of building decoration, prefabricated buildings have gradually become popular, characterized by simple and efficient decoration, enabling quick renovation and low VOC emissions. For prefabricated buildings, especially in hotel and commercial buildings where the replacement cycle is typically 5-10 years, lightweight and recyclable materials have naturally become the first choice for designers.

[0003] my country boasts abundant bamboo resources, with an annual bamboo production of approximately 150 million tons, making it an ideal green and renewable alternative material. Bamboo also has a strong carbon sequestration capacity; for example, moso bamboo absorbs 24.31 tons of carbon dioxide per hectare annually, classifying it as a carbon-negative material. In response to the policy of replacing plastics with bamboo, local governments and organizations are currently providing significant policy support for bamboo fiber, with applications spanning the building decoration, automotive, daily necessities, and textile and home textile sectors. For instance, in the building decoration field, as covered by this patent, it can be used as wall panels, flooring, and ceilings. It possesses advantages such as a pleasant odor, low VOC content, and lightweight yet high strength.

[0004] Currently, the main sound-absorbing panels in the industry include fiberglass boards, rock wool boards, polyester boards, and foam boards. Fiberglass boards, primarily made of glass fiber, offer good mid-to-high frequency sound absorption, but inhaling the fiber can be harmful, and the construction environment is often unpleasant. Rock wool boards have excellent fire resistance, but lower strength, and their fiber structure is similar to glass fiber, posing health risks. Polyester boards are made of polyester fibers, using high-melting-point polyester fibers as reinforcement and low-melting-point polyester fibers as binders. They offer advantages such as low VOCs, diverse colors, and ease of processing. However, polyester fibers can drip, resulting in poor flame retardancy, and their low-frequency sound absorption is relatively poor. Foam boards, mainly made of EVA and PU, offer good sound absorption, but lack overall rigidity, requiring reinforcement. This reinforcement process uses chemical adhesives, leading to VOC issues. Furthermore, foam itself is prone to aging and powdering, resulting in a short lifespan.

[0005] Patent CN 117341322 A discloses a bamboo fiber sound-absorbing felt made of bamboo fiber composite material felt on both sides and a PET thin plate core layer in the middle, which is reinforced by needle punching process. It has advantages such as being lightweight and having excellent sound absorption performance.

[0006] Patent CN 113954402 B discloses a sound-absorbing panel made from polyester-polyamide mixed fibers and polyester fibers, which achieves an antibacterial effect through ultrasonic treatment in a nano-copper solution. This achieves long-term effective antibacterial properties while maintaining a certain level of sound absorption.

[0007] Currently, mainstream sound-absorbing panels have the following drawbacks:

[0008] 1) The poor environment created by decorating with fiberglass boards and rock wool boards can negatively impact human health;

[0009] 2) Rock wool boards have poor strength and provide no support;

[0010] 3) Polyester boards are difficult to effectively retard flames and have poor overall low-frequency sound absorption;

[0011] 4) Foam boards are not durable and have VOC issues. Summary of the Invention

[0012] To address the aforementioned problems, this invention provides a flame-retardant bamboo fiber sound-absorbing board, its preparation method, and its application. This invention applies bamboo fiber to sound-absorbing boards in the building decoration field, significantly replacing currently used high-carbon-emission raw materials such as fiberglass and rock wool, thus achieving energy conservation and emission reduction. Simultaneously, it solves the problems of poor low-frequency sound absorption, insufficient strength, and difficulty in meeting flame-retardant standards inherent in the aforementioned sound-absorbing boards.

[0013] To achieve the above objectives, the present invention provides the following technical solution:

[0014] This invention provides a method for preparing a flame-retardant bamboo fiber sound-absorbing board, comprising the following steps:

[0015] 1) After mixing 4080 polyester fiber with conventional polyester fiber, the mixture is opened, carded, cross-laid and needle-punched in sequence to obtain polyester nonwoven fabric;

[0016] The melting point of the 4080 polyester fiber is 110~150℃, and the melting point of the conventional polyester fiber is 255~265℃.

[0017] 2) After mixing 4080 polyester fiber with bamboo fiber, the mixture is opened, carded, cross-laid and needle-punched in sequence to obtain bamboo fiber composite felt;

[0018] The melting point of the 4080 polyester fiber is 110~150℃;

[0019] 3) The polyester nonwoven fabric described in step 1) is arranged on the upper and lower surfaces of the bamboo fiber composite felt described in step 2) and then needle-punched, hot-melted and cooled in sequence to obtain a flame-retardant bamboo fiber sound-absorbing board; the bamboo fiber is subjected to flame-retardant modification treatment.

[0020] Preferably, the 4080 polyester fiber described in steps 1) and 2) has a melting point of 110~150℃, a fineness of 6-8 dtex, and a limiting oxygen index >27.

[0021] Preferably, the conventional polyester fiber in step 1) has a melting point of 255~265℃, a fineness of 3~6 dtex, and a limiting oxygen index >27;

[0022] Preferably, the mass ratio of the 4080 polyester fiber to the conventional polyester fiber in step 1) is 3:7;

[0023] The opening conditions include: pre-opening speed of 1100 r / min; main opening speed of 1800 r / min;

[0024] The conditions for combing include: cylinder 950 r / min; doffer 110 r / min; linear speed ratio 8:1; net weight 16 g / m².

[0025] The conditions for laying the mesh include: a laying angle of 35°; 13 layers; and a draw rate of 12 m / min.

[0026] The acupuncture conditions include: 900 pre-needles / min; 2300 main needle insertions / min; needle depth 8–9 mm; needle plate density 140 needles / m².

[0027] Preferably, in step 2), the mass ratio of 4080 polyester fiber to bamboo fiber is 1:1;

[0028] The opening conditions include: pre-opening speed of 700 r / min; main opening speed of 1000 r / min.

[0029] The conditions for combing include: cylinder speed 880 r / min, doffer speed 105 r / min, linear speed ratio 7:1; net weight 25 g / m².

[0030] The conditions for cross-laying include: a laying angle of 35°, a speed of 6 m / min, and 100 layers;

[0031] The acupuncture conditions include: 900 pre-needles / min; 1800 main needle insertions / min; needle depth 9–12 mm; needle plate density 140 needles / m².

[0032] Preferably, the bamboo fiber in step 2) includes bamboo fiber and / or moso bamboo fiber; the bamboo fiber has a fiber length of 70~200mm, a fiber diameter of 0.1~0.2mm, a moisture content of ≤15%, and a pH value of <8;

[0033] The method for flame-retardant modification of bamboo fiber includes the following steps:

[0034] a. The bamboo fiber is dried at 100°C for 24 hours, and the moisture content is less than 3% to obtain dried bamboo fiber.

[0035] b. The dried bamboo fibers described in step a are placed in an impregnation solution for impregnation to obtain impregnated bamboo fibers;

[0036] The impregnation solution comprises the following components in parts by weight: 8-12 parts diammonium hydrogen phosphate, 3-4 parts pentaerythritol, 0.1 parts silane coupling agent (model KH-550), 0.5-1 parts glyoxal, and 100-150 parts water.

[0037] The volume ratio of the dried bamboo fiber to the impregnation liquid is 1:10;

[0038] The impregnation conditions include: a temperature of 40~60℃, an oscillation frequency of 30~50Hz, and a time of 1~2h;

[0039] c. Dry the bamboo fiber impregnated in step b;

[0040] The drying conditions include: first, treating at 60-80℃ for 30-60 minutes, then treating at 120-150℃ for 10-20 minutes, and finally treating at 60-80℃ for 12-24 hours.

[0041] Preferably, the basis weight of the polyester nonwoven fabric in step 3) is 200~500 gsm; the basis weight of the bamboo fiber composite felt is 600~3000 gsm, and the fiber content is 50~70%.

[0042] Preferably, the acupuncture conditions in step 3) include: a needle depth of 10-12 mm and a needle density of 40-60 needles / cm. 2 ;

[0043] The conditions for the thermal melting include: a temperature of 180~210℃ and a speed of 3~5m / min;

[0044] The cooling conditions include: cooling water temperature < 50°C.

[0045] The present invention also provides a flame-retardant bamboo fiber sound-absorbing board prepared by the preparation method described in the above technical solution.

[0046] The present invention also provides the application of the flame-retardant bamboo fiber sound-absorbing board described in the above technical solution in improving the low-frequency sound absorption effect and / or flame-retardant performance of the board.

[0047] The beneficial effects of this invention are:

[0048] 1) By replacing high-carbon-emission fiber products such as glass fiber, rock wool, and polyester fiber in traditional sound-absorbing panels with bamboo fiber, energy conservation and carbon reduction can be achieved.

[0049] 2) Using bamboo fiber with a lower fineness to produce sound-absorbing panels achieves better sound absorption at low frequencies, solving the problem of poor low-frequency sound absorption in traditional fiber composite sound-absorbing panels.

[0050] 3) By impregnating and modifying bamboo fiber for flame retardancy, a good flame retardant effect and low heat release can be achieved simply and efficiently. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0052] Figure 1 This is a schematic diagram of the cross-sectional structure of the flame-retardant bamboo fiber sound-absorbing board of the present invention. 1 is polyester nonwoven fabric, and 2 is bamboo fiber composite felt.

[0053] Figure 2 This is a production line flow diagram for the flame-retardant bamboo fiber sound-absorbing board of the present invention. 3 is bamboo fiber and 4080 polyester fiber, 4 is an opening device, 5 is a cotton blending device, 6 is a carding machine, 7 is a web laying machine, 8 is a needle punching machine, 9 is a polyester nonwoven fabric unwinding device, 10 is a rotary screen drying oven, 11 is a pressure roller and a cold roller, and 12 is a cutting device. Detailed Implementation

[0054] This invention provides a method for preparing a flame-retardant bamboo fiber sound-absorbing board, comprising the following steps:

[0055] 1) After mixing 4080 polyester fiber with conventional polyester fiber, the mixture is opened, carded, cross-laid and needle-punched in sequence to obtain polyester nonwoven fabric;

[0056] The melting point of the 4080 polyester fiber is 110~150℃, and the melting point of the conventional polyester fiber is 255~265℃.

[0057] 2) After mixing 4080 polyester fiber with bamboo fiber, the mixture is opened, carded, cross-laid and needle-punched in sequence to obtain bamboo fiber composite felt;

[0058] The melting point of the 4080 polyester fiber is 110~150℃;

[0059] 3) The polyester nonwoven fabric described in step 1) is arranged on the upper and lower surfaces of the bamboo fiber composite felt described in step 2) and then needle-punched, hot-melted and cooled in sequence to obtain a flame-retardant bamboo fiber sound-absorbing board; the bamboo fiber is subjected to flame-retardant modification treatment.

[0060] This invention involves mixing 4080 polyester fiber with conventional polyester fiber, followed by sequential opening, carding, cross-laying, and needle punching to obtain a polyester nonwoven fabric. The melting point of the 4080 polyester fiber is 110-150℃, and the melting point of the conventional polyester fiber is 255-265℃. Both the 4080 polyester fiber and the conventional polyester fiber undergo flame-retardant modification treatment. In this invention, the preferred melting point of the 4080 polyester fiber is 110-150℃, the preferred fineness is 6-8 dtex, and the limiting oxygen index is >27. In this invention, the 4080 polyester fiber is sourced from Yangzhou Tianfulong Automotive Interior Fiber Co., Ltd. (product specification FLR101 4De*51mm). In this invention, the preferred melting point of the conventional polyester fiber is 255-265℃, the preferred fineness is 3-6 dtex, and the limiting oxygen index is >27. In this invention, the conventional polyester fiber is sourced from Yangzhou Tianfulong Automotive Interior Fiber Co., Ltd. (product specification FLR102 6De*51mm). In this invention, the preferred mass ratio of the 4080 polyester fiber to conventional polyester fiber is 3:7. The opening conditions preferably include: pre-opening speed of 1100 r / min; main opening speed of 1800 r / min; carding conditions include: cylinder speed of 950 r / min; doffer speed of 110 r / min; linear speed ratio of 8:1; net weight of 16 g / m²; web laying conditions include: web laying angle of 35°; 13 layers; draft of 12 m / min; and needle punching conditions include: pre-needle punching of 900 times / min; main needle punching of 2300 times / min; needle depth of 8–9 mm; and needle density of 140 needles / m².

[0061] This invention involves mixing 4080 polyester fiber and bamboo fiber, followed by sequential opening, carding, cross-laying, and needle punching to obtain a bamboo fiber composite felt. The melting point of the 4080 polyester fiber is 110~150℃. The 4080 polyester fiber undergoes flame-retardant modification treatment. In this invention, the preferred mass ratio of the 4080 polyester fiber to the bamboo fiber is 1:1. In this invention, the opening conditions preferably include: a pre-opening speed of 700 r / min; a main opening speed of 1000 r / min; the carding conditions include: cylinder speed of 880 r / min, doffer speed of 105 r / min, linear speed ratio of 7:1; and a net weight of 25 g / m²; the cross-laying conditions include: a laying angle of 35°, a speed of 6 m / min, and 100 layers; and the needle-punching conditions include: pre-punching of 900 times / min; main needle-punching of 1800 times / min; needle depth of 9–12 mm; and a needle density of 140 needles / m². In this invention, the bamboo fiber preferably includes *Phyllostachys edulis* fiber and / or *Phyllostachys moso* fiber; the bamboo fiber has a fiber length of 70–200 mm, a fiber diameter of 0.1–0.2 mm, a moisture content of ≤15%, and a pH value of <8.

[0062] In this invention, the method for flame-retardant modification of bamboo fiber preferably includes the following steps:

[0063] a. The bamboo fiber is dried at 100°C for 24 hours, and the moisture content is less than 3% to obtain dried bamboo fiber.

[0064] b. The dried bamboo fibers described in step a are placed in an impregnation solution for impregnation to obtain impregnated bamboo fibers;

[0065] The impregnation solution comprises the following components in parts by weight: 8-12 parts diammonium hydrogen phosphate, 3-4 parts pentaerythritol, 0.1 parts silane coupling agent (KH-550), 0.5-1 parts glyoxal, and 100-150 parts water;

[0066] The volume ratio of the dried bamboo fiber to the impregnation liquid is 1:10;

[0067] The impregnation conditions include: a temperature of 40~60℃, an oscillation frequency of 30~50Hz, and a time of 1~2h;

[0068] c. Dry the bamboo fiber impregnated in step b;

[0069] The drying conditions include: first, treatment at 60-80℃ for 30-60 minutes, then treatment at 120-150℃ for 10-20 minutes (to promote cross-linking reaction and improve the bonding effect between flame retardant and fiber), and finally treatment at 60-80℃ for 12-24 hours.

[0070] This invention involves arranging the polyester nonwoven fabric on the upper and lower surfaces of the bamboo fiber composite felt, followed by sequential needle punching, hot melting, and cooling to obtain a flame-retardant bamboo fiber sound-absorbing board; the bamboo fiber undergoes flame-retardant modification treatment. In this invention, the basis weight of the polyester nonwoven fabric is preferably 200-500 gsm; the basis weight of the bamboo fiber composite felt is preferably 600-3000 gsm, and the fiber content is preferably 50-70%. In this invention, the needle punching conditions preferably include: needle depth of 10-12 mm and needle density of 40-60 needles / cm. 2 In this invention, the preferred conditions for the thermal melting include: a temperature of 180~210℃ and a melting speed of 3~5 m / min. In this invention,

[0071] The preferred cooling conditions include: cooling water temperature < 50°C.

[0072] The present invention also provides a flame-retardant bamboo fiber sound-absorbing board prepared by the preparation method described in the above technical solution.

[0073] The present invention also provides the application of the flame-retardant bamboo fiber sound-absorbing board described in the above technical solution in improving the low-frequency sound absorption effect and / or flame-retardant performance of the board.

[0074] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0075] Example 1

[0076] Product structure: Symmetrical three-layer structure, polyester nonwoven fabric + bamboo fiber composite felt + polyester nonwoven fabric

[0077] Raw material parameters:

[0078] Polyester nonwoven fabric: 4080 polyester fiber (Yangzhou Fuwei Composite Materials Co., Ltd., melting point 130℃, fineness 4dtex, limiting oxygen index >27%), conventional polyester fiber (Yangzhou Tianfulong Automotive Interior Fiber Co., Ltd., melting point 260℃, fineness 6dtex, limiting oxygen index >27%), mass ratio 30:70; polyester nonwoven fabric basis weight 300gsm.

[0079] Raw materials for bamboo fiber composite felt: bamboo fiber (Cizhu fiber, length 120mm, diameter 0.15mm, moisture content 10%, pH value 7.2, flame retardant modified) and 4080 polyester fiber (same as above), mass ratio 50:50; bamboo fiber composite felt weight 1500gsm.

[0080] Process parameters

[0081] Flame retardant modification of bamboo fiber:

[0082] a. The bamboo fiber is dried at 100°C for 24 hours, and the moisture content is less than 3% to obtain dried bamboo fiber.

[0083] b. The dried bamboo fibers described in step a are placed in an impregnation solution for impregnation to obtain impregnated bamboo fibers;

[0084] The impregnation solution comprises the following components in parts by weight: 12 parts diammonium hydrogen phosphate, 4 parts pentaerythritol, 0.1 parts silane coupling agent (KH-550), 0.5 parts glyoxal, and 150 parts water.

[0085] The ratio of the dried bamboo fiber to the impregnation solution is 1:10;

[0086] The impregnation conditions include: a temperature of 60°C, an oscillation frequency of 30Hz, and a time of 1.5h.

[0087] c. Dry the bamboo fiber impregnated in step b;

[0088] The drying conditions include: first, treatment at 80°C for 30-60 minutes, then treatment at 120°C for 20 minutes (to promote cross-linking reaction and improve the bonding effect between flame retardant and fiber), and finally treatment at 80°C for 24 hours.

[0089] Preparation of polyester nonwoven fabric:

[0090] Fiber mixing → Pre-opening (1100r / min) → Main opening (1800r / min) → Carding (cylinder 950r / min, doffer 110r / min, linear speed ratio 8:1, net weight 16g / m²) → Cross-laying (angle 35°, number of layers 13, draft 12m / min) → Needling (pre-needling 900 times / min, main needleling 2300 times / min, needle depth 8.5mm, needle density 140 needles / m²) → Rolling.

[0091] Preparation of bamboo fiber composite felt:

[0092] Fiber mixing → pre-opening (700 r / min) → main opening (1000 r / min) → carding (cylinder 880 r / min, doffer 105 r / min, linear speed ratio 7:1, net weight 25 g / m²) → cross-laying (angle 35°, speed 6 m / min, number of layers 100) → needle punching (pre-needle punching 900 times / min, main needle punching 1800 times / min, needle depth 10 mm, needle plate density 140 needles / m²).

[0093] Composite molding:

[0094] Polyester nonwoven fabric is bonded to the upper and lower surfaces of the composite felt → composite needle punching (needle depth 11mm, needle density 50 needles / cm²) → hot pressing into a plate (temperature 200℃, speed 4m / min) → cooling (cooling water 45℃) → cutting (size as needed).

[0095] Product performance:

[0096] Board thickness: 12mm; Board weight: 3500gsm; Low-frequency sound absorption coefficient (500Hz): 0.45, GB / T20247-2006; Oxygen index: 28%, GB / T2406.2-2009; VOC content: 0.45mg / m³, ISO 12219-2:2012; Flexural strength: 15MPa, GB / T 1449; Environmental friendliness and workability: Excellent, non-irritating;

[0097] Example 2

[0098] The difference between this embodiment and Embodiment 1 is that the type of bamboo fiber used is the same as in Embodiment 1, while the other process steps and parameters are the same.

[0099] Raw material selection:

[0100] The bamboo fiber is made from moso bamboo fiber with a fiber length of 150mm, a fiber diameter of 0.2mm, a moisture content of 12%, and a pH value of 7.5. It has been treated with impregnation and flame retardant modification.

[0101] Product performance:

[0102] Board thickness: 12mm; Board weight: 3500gsm; Low-frequency sound absorption coefficient (500Hz): 0.35; Oxygen index: 28%; VOC content: 0.58mg / m³; Flexural strength: 16MPa; Environmental friendliness and workability: Excellent, non-irritating;

[0103] Example 3

[0104] This embodiment focuses on adjusting the basis weight of bamboo fiber composite felt and the ultrasonic parameters in the impregnation and flame retardant modification process; the rest is the same as in Example 1.

[0105] Raw material and process adjustments:

[0106] In the impregnation flame retardant modification step, the ultrasonic oscillation frequency is 40Hz, the treatment time is 1.5h, and the impregnation is repeated twice.

[0107] Product performance:

[0108] Low-frequency sound absorption coefficient (500Hz): 0.45, oxygen index: 30%, flexural strength: 13MPa, VOC content: 0.75mg / m³ 3 .

[0109] Comparative Example 1

[0110] (Traditional fiberglass sound-absorbing panel)

[0111] Raw materials and processes:

[0112] Sound-absorbing panels were made by replacing bamboo fiber with glass fiber (Jushi Group 362H), and the rest were the same as in Example 1.

[0113] Product performance:

[0114] Low-frequency sound absorption coefficient 0.15, oxygen index 22%, flexural strength 20MPa, glass fiber is prone to detachment during construction, VOC content 1.2mg / m³ 3 It poses a risk of irritating the human respiratory tract.

[0115] Comparative Example 2

[0116] (Traditional polyester sound-absorbing panel)

[0117] Raw materials and processes:

[0118] The bamboo fiber felt in Example 1 was replaced by a mixture of conventional polyester fiber and 4080 polyester fiber in a 7:3 ratio, and the rest was the same as in Example 1.

[0119] Product performance:

[0120] Low-frequency sound absorption coefficient 0.30, oxygen index 24%, flexural strength 6MPa, VOC content 0.8mg / m³ 3 .

[0121] Comparative Example 3

[0122] (Unmodified bamboo fiber sound-absorbing board)

[0123] Raw materials and processes:

[0124] The same structure and production process as in Example 1 were used, but the bamboo fiber was not impregnated with flame retardant and the polyester fiber was not modified with flame retardant.

[0125] Product performance:

[0126] Low-frequency sound absorption coefficient 0.42, oxygen index 18%, flexural strength 14MPa, VOC content 0.5mg / m³ 3 .

[0127] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a flame-retardant bamboo fiber sound-absorbing board, characterized in that, Includes the following steps: 1) After mixing 4080 polyester fiber with conventional polyester fiber, the mixture is opened, carded, cross-laid and needle-punched in sequence to obtain polyester nonwoven fabric; The melting point of the 4080 polyester fiber is 110~150℃, and the melting point of the conventional polyester fiber is 255~265℃. 2) After mixing 4080 polyester fiber with bamboo fiber, the mixture is opened, carded, laid into a web and needle punched in sequence to obtain bamboo fiber composite felt; The melting point of the 4080 polyester fiber is 110~150℃; 3) The polyester nonwoven fabric described in step 1) is arranged on the upper and lower surfaces of the bamboo fiber composite felt described in step 2) and then needle-punched, hot-melted and cooled in sequence to obtain a flame-retardant bamboo fiber sound-absorbing board; the bamboo fiber is subjected to flame-retardant modification treatment.

2. The preparation method according to claim 1, characterized in that, The 4080 polyester fiber mentioned in steps 1) and 2) has a melting point of 110~150℃, a fineness of 6-8 dtex, and a limiting oxygen index of >27.

3. The preparation method according to claim 1, characterized in that, Step 1) The conventional polyester fiber has a melting point of 255~265℃, a fineness of 3~6 dtex, and a limiting oxygen index of >27.

4. The preparation method according to claim 1, characterized in that, Step 1) The mass ratio of the 4080 polyester fiber to the conventional polyester fiber is 3:7; The opening conditions include: pre-opening speed of 1100 r / min; main opening speed of 1800 r / min; The conditions for combing include: cylinder 950 r / min; doffer 110 r / min; linear speed ratio 8:1; net weight 16 g / m². The conditions for laying the mesh include: a laying angle of 35°; 13 layers; and a draw rate of 12 m / min. The acupuncture conditions include: 900 pre-needles / min; 2300 main needle punctures / min; needle depth 8-9 mm; needle plate density 140 needles / m².

5. The preparation method according to claim 1, characterized in that, Step 2) The mass ratio of the 4080 polyester fiber to the bamboo fiber is 1:1; The opening conditions include: pre-opening speed of 700 r / min; main opening speed of 1000 r / min; The conditions for combing include: cylinder speed 880 r / min, doffer speed 105 r / min, linear speed ratio 7:1; net weight 25 g / m². The conditions for cross-laying include: a laying angle of 35°, a speed of 6 m / min, and 100 layers; The acupuncture conditions include: 900 pre-needles / min; 1800 main acupunctures / min; needle depth 9–12 mm; and needle plate density 140 needles / m².

6. The preparation method according to claim 1, characterized in that, Step 2) The bamboo raw fiber includes bamboo fiber and / or moso bamboo fiber; the bamboo raw fiber has a fiber length of 70~200mm, a fiber diameter of 0.1~0.2mm, a moisture content of ≤15%, and a pH value of <8; The method for flame-retardant modification of bamboo fiber includes the following steps: a. The bamboo fiber is dried at 100°C for 24 hours, and the moisture content is less than 3% to obtain dried bamboo fiber. b. The dried bamboo fibers described in step a are placed in an impregnation solution for impregnation to obtain impregnated bamboo fibers; The impregnation solution comprises the following components in parts by weight: 8-12 parts diammonium hydrogen phosphate, 3-4 parts pentaerythritol, 0.1 parts silane coupling agent, 0.5-1 parts glyoxal, and 100-150 parts water; The volume ratio of the dried bamboo fiber to the impregnation liquid is 1:10; The impregnation conditions include: a temperature of 40~60℃, an oscillation frequency of 30~50Hz, and a time of 1~2h; c. Dry the bamboo fiber impregnated in step b; The drying conditions include: first, treating at 60-80℃ for 30-60 minutes, then treating at 120-150℃ for 10-20 minutes, and finally treating at 60-80℃ for 12-24 hours.

7. The preparation method according to claim 1, characterized in that, Step 3) The basis weight of the polyester nonwoven fabric is 200~500 gsm; the basis weight of the bamboo fiber composite felt is 600~3000 gsm, and the fiber content is 50~70%.

8. The preparation method according to claim 1, characterized in that, Step 3) The acupuncture conditions include: needle depth of 10-12 mm and needle density of 40-60 needles / cm. 2 ; The conditions for the thermal melting include: a temperature of 180~210℃ and a speed of 3~5m / min; The cooling conditions include: cooling water temperature < 50°C.

9. A flame-retardant bamboo fiber sound-absorbing board prepared by the preparation method according to any one of claims 1 to 8.

10. The flame-retardant bamboo fiber sound-absorbing board of claim 9 is used to improve the low-frequency sound absorption effect and / or flame-retardant performance of the board.

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