Phenolic resin-based melt-blown non-woven material for sound absorption and noise reduction and preparation method thereof

Abstract

The invention discloses a phenolic resin-based melt-blown non-woven material for sound absorption and noise reduction and a preparation method thereof, and relates to the technical field of sound absorption and noise reduction, the preparation method of the melt-blown non-woven material comprises the following steps: carrying out vacuum drying on modified phenolic resin, then carrying out melt-blowing, immersing the obtained melt-blown material in a crosslinking bath, carrying out heating curing, washing, and drying to obtain the phenolic resin-based melt-blown non-woven material for sound absorption and noise reduction. A cross-linked material is obtained; and ultrasonically immersing the cross-linked material in the silanization surface treating agent, and drying to obtain the melt-blown non-woven material. By introducing modified components such as resorcinol, organic silicon, boric acid and DOPO, the high temperature resistance, flame retardance and flexibility of the phenolic resin are improved, and the requirements of melt-blowing melt spinning are met; the carbon nanotubes are modified through silane coupling, and the carbon nanotubes are uniformly combined in a cross-linked network, so that the antistatic property of the melt-blown non-woven fabric is remarkably improved, and the service life of the melt-blown non-woven fabric is prolonged; meanwhile, due to the high specific surface area and thermal stability of the carbon nanotubes, the sound absorption and noise reduction performance and the high temperature resistance of the material are further enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of sound absorption and noise reduction, and particularly relates to a phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction and a preparation method thereof. Background Art

[0002] With the acceleration of the modern industrial and urbanization processes, noise pollution has become one of the important factors affecting people's quality of life. Therefore, the development of efficient sound absorption and noise reduction materials has become a research hotspot in the field of materials science. Nonwoven materials, due to their unique structures and properties, show broad application prospects in the field of sound absorption and noise reduction.

[0003] As an efficient fiber preparation method, the meltblowing technology can produce ultrafine fibers, thereby significantly increasing the specific surface area and porosity of the material, and further enhancing its sound absorption and noise reduction performance. However, most of the existing meltblown nonwoven materials are based on thermoplastic polymers such as polypropylene (PP), and their heat resistance and flame retardancy are poor.

[0004] In recent years, by applying the optimized phenolic resin-based meltblown nonwoven material to the field of sound absorption and noise reduction, the high temperature resistance and flame retardancy of the meltblown nonwoven material can be further improved, and its application scenarios can be broadened. However, phenolic resin itself has good insulation properties and is prone to static charge accumulation. After long-term use, some particulate dust will be adsorbed on the surface layer of the material due to electrostatic attraction, thus blocking the pores, and further reducing the channels for sound waves to enter the interior of the material, resulting in a decrease in the sound absorption and noise reduction effect.

[0005] Chinese Patent CN114045598B discloses a lightweight kapok strip yarn fabric sound-absorbing material, its preparation method and application. An ultra-thin PP meltblown cloth is placed on one side of a kapok / hollow polyester fiber web, and after needling reinforcement and winding, a composite fiber web is obtained. After being twisted by a roving frame and then spirally wound with a PP meltblown cloth on the outer layer, kapok strip yarn is obtained. The kapok strip yarn and the hollow polyester yarn are vertically interwoven to form a kapok strip yarn fabric sound-absorbing material. The sound-absorbing material of this invention has simple composition and is lightweight, but its high temperature resistance and flame retardancy are poor, which is not conducive to its use in high temperature or fireproof environment conditions.

[0006] Therefore, there is an urgent need to develop a phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction and a preparation method thereof, so that it has excellent high temperature resistance, flame retardancy and sound absorption and noise reduction performance, and broadens its application in environments with high requirements for high temperature or fire prevention. Summary of the Invention

[0007] Aiming at the existing technical problems, the purpose of the present invention is to provide a phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction and a preparation method thereof. The meltblown nonwoven material of the present invention has good high temperature resistance and flame retardancy, excellent sound absorption and noise reduction effect, long service life, and diverse application scenarios.

[0008] Technical solution of the present invention: A preparation method of a phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction, comprising the following steps: S1: Vacuum-dry the modified phenolic resin and then perform meltblowing to obtain a meltblown material; S2: Immerse the meltblown material obtained in step S1 in a crosslinking bath, raise the temperature for curing, wash, and dry to obtain a crosslinked material; S3: Ultrasonically immerse the crosslinked material obtained in step S2 in a silanization surface treatment agent and dry to obtain a meltblown nonwoven material.

[0009] Further, in step S1, the conditions for vacuum drying are vacuum drying at 60-120°C for 4-8 h.

[0010] Further, in step S1, the operating conditions for meltblowing are that the melt temperature is 120-160°C, the hot air drawing temperature is 170-210°C, and the receiving distance during drawing is 25-50 cm.

[0011] Further, the modified phenolic resin in step S1 is prepared by the following steps: Q1: Mix resorcinol and an aqueous sodium hydroxide solution, heat to 70-80°C, stir and react for 30-40 min, dropwise add epichlorohydrin, dropwise add an aqueous sodium hydroxide solution to adjust the pH value to 9-10, keep stirring at a constant temperature for 1-2 h, cool to -3-4°C, and adjust the pH to neutral to obtain a phenolic compound; Q2: Mix the phenolic compound obtained in step Q1, phenol, an aldehyde compound, and a divalent metal salt for polycondensation reaction to obtain a phenolic product; Q3: Mix the phenolic product obtained in step Q2 with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heat to 160-170°C and react for 6-8 h, cool to 65-75°C, and dehydrate to obtain a phosphorus-containing phenolic resin compound; Q4: Mix the phosphorus-containing phenolic resin compound obtained in step Q3 with organosilicon, heat to 90-110°C and react for 3-4 h, adjust the pH value to 2.5-3.5, add boric acid, keep the temperature for reaction for 2-2.5 h, adjust the pH value to 5-5.5, wash, distill under reduced pressure, and dry to obtain a modified phenolic resin.

[0012] As a preferred scheme, the molar ratio of resorcinol to epichlorohydrin is 1:(0.95-1.15).

[0013] As a preferred scheme, the mass ratio of the phenolic compound, phenol, and aldehyde compound is (0.25-0.55):1:(0.6-1).

[0014] Preferably, the aldehyde compound is formaldehyde.

[0015] Preferably, the divalent metal salt is zinc acetate.

[0016] As a preferred embodiment, the mass ratio of the phenolic product to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(3-5).

[0017] As a preferred embodiment, the mass ratio of the phosphorus-containing phenolic resin compound, silicone, and boric acid is 1:(0.06-0.1):(0.04-0.06).

[0018] Preferably, the silicone is diethoxymethylvinylsilane.

[0019] Furthermore, the specific operation steps and parameters of step S2 are as follows: Immerse the meltblown material obtained in step S1 in a crosslinking bath at room temperature for 0.5-2 h, heat it from room temperature to 100-120 °C at a heating rate of 10-30 °C / h, hold for reaction for 0.5-3 h, wash 4 times with distilled water, and dry at 105-125 °C for 3-5 h to obtain a crosslinked material.

[0020] Furthermore, the crosslinking bath is a composition of an acid solution and a paraformaldehyde solution.

[0021] As a preferred embodiment, in the composition, the volume ratio of the acid solution to the paraformaldehyde solution is 1:1.

[0022] As a preferred embodiment, the mass fraction of the acid solution is 10-25 wt%; the mass fraction of the paraformaldehyde solution is 10-25 wt%.

[0023] Preferably, the acid solution is any one or more of hydrochloric acid solution, phosphoric acid solution, oxalic acid solution, and sulfuric acid solution.

[0024] Furthermore, the specific operation steps and parameters of step S3 are as follows: Ultrasonically immerse the crosslinked material obtained in step S2 in a silanized surface treatment agent for 15-25 min, add an initiator, heat to 60-90 °C, stir at a constant temperature for 6-8 h, then raise the temperature to 90-120 °C, stir at a constant temperature for 10-20 min, wash, and dry to obtain a meltblown nonwoven material.

[0025] Furthermore, the silanized surface treatment agent is silanized modified carbon nanotubes, and its preparation method is: Mix carbon nanotubes with distilled water, add vinyltriethoxysilane, and heat to 45-65 °C for reaction for 2-4 h to obtain a surface treatment agent.

[0026] As a preferred embodiment, the mass ratio of the carbon nanotubes to vinyltriethoxysilane is 1:(0.2-0.5).

[0027] Preferably, the dosage of the initiator is 3% of the crosslinking material.

[0028] Preferably, the initiator is benzoyl peroxide.

[0029] The present invention also provides a phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction, which is prepared by the above preparation method.

[0030] The phosphorus-containing phenolic resin compound provided by the present invention incorporates epoxy groups through the reaction of the hydroxyl groups of resorcinol with the chlorine groups on epichlorohydrin. After the condensation reaction of phenolic substances, the high-temperature resistance is enhanced; then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) is introduced to react with the epoxy groups, greatly enhancing the flame retardancy and high-temperature resistance of the compound.

[0031] The modified phenolic resin material provided by the present invention further modifies the phenolic resin with organosilicon, introducing a silicon-containing flexible chain, diethoxymethylvinylsilane, significantly enhancing the flexibility and spinnability of the resin; at the same time, the dual modification effect of boric acid can improve the thermal degradation performance through reaction with hydroxyl groups and form a more stable three-dimensional crosslinked network, greatly enhancing the thermal stability to meet the requirements of meltblown melt spinning.

[0032] A phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction disclosed by the present invention is prepared by modifying carbon nanotubes with vinyltriethoxysilane to obtain a surface treatment agent. During the immersion process, the immersion conditions are controlled so that the double bonds on vinyltriethoxysilane crosslink with the double bonds on diethoxymethylvinylsilane in the organosilicon, thereby uniformly binding carbon nanotubes in the crosslinked network, further enhancing the antistatic property of the meltblown nonwoven fabric, making it less likely to adsorb dust particles and having a longer service life. In addition, carbon nanotubes have good thermal stability and an extremely high specific surface area, which is beneficial to improving the sound absorption and noise reduction effect and high-temperature resistance to a certain extent.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) By introducing modified components such as resorcinol, organosilicon, boric acid, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, the present invention significantly enhances the high-temperature resistance, flame retardancy, and flexibility of phenolic resin, while meeting the requirements of meltblown melt spinning.

[0034] (2) By modifying carbon nanotubes with vinyltriethoxysilane and uniformly binding carbon nanotubes in the crosslinked network, the present invention significantly enhances the antistatic property of the meltblown nonwoven fabric and extends its service life; at the same time, the high specific surface area and thermal stability of carbon nanotubes further enhance the sound absorption and noise reduction performance and high-temperature resistance of the material.

[0035] (3)The melt-blown nonwoven material of the present invention has good high-temperature resistance and flame retardancy, excellent sound absorption and noise reduction effects, a long service life, and diverse application scenarios. Detailed implementation manners

[0036] The present invention will be described below in conjunction with specific implementation manners. It should be noted that the following examples are examples of the present invention, only for illustrating the present invention, rather than limiting the present invention. Without departing from the gist or scope of the present invention, other combinations and various improvements within the concept of the present invention can be made.

[0037] For the convenience of those skilled in the art to implement the present invention, the manufacturers of some raw materials in the examples and comparative examples are described as follows: Carbon nanotubes: particle size 20 nm; other raw materials are not specially stated and can be purchased from the market.

[0038] Prepare each melt-blown nonwoven material according to the ratios and preparation methods of the raw materials specified in the following examples and comparative examples.

[0039] Preparation Example 1 The preparation method of modified phenolic resin A includes the following steps: Q1: Mix 0.5 mol of resorcinol and 200 mL of 25 wt% sodium hydroxide aqueous solution, heat to 75 °C, stir and react for 35 min, dropwise add 0.525 mol of epichlorohydrin, and then dropwise add 25 wt% sodium hydroxide aqueous solution to adjust the pH value to 10, keep stirring at a constant temperature for 1.5 h, cool down to 0 °C, add 2 mol / L hydrochloric acid aqueous solution to adjust the pH value to 7, and obtain phenolic compounds; Q2: Mix 24 g of phenolic compounds obtained in step Q1, 60 g of phenol, 48 g of formaldehyde, 100 mL of distilled water, and 3.4 g of zinc acetate, add 6 mol / L hydrochloric acid aqueous solution to adjust the pH value to 4, heat to 95 °C and react for 1.5 h to obtain phenolic products; Q3: Mix 30 g of phenolic products obtained in step Q2 and 120 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heat to 165 °C and react for 7 h, cool down to 70 °C, and dehydrate to obtain a phosphorus-containing phenolic resin compound; Q4: Mix 30 g of the phosphorus-containing phenolic resin compound obtained in step Q3 and 2.4 g of diethoxymethylvinylsilane, heat to 95 °C and react for 4 h, add 6 mol / L hydrochloric acid aqueous solution to adjust the pH value to 3, add 1.5 g of boric acid, keep the reaction at a constant temperature for 2 h, add 25 wt% sodium hydroxide aqueous solution to adjust the pH value to 5, wash twice with distilled water, carry out vacuum distillation at 170 °C for 2 h, and vacuum dry at 120 °C for 6 h to obtain modified phenolic resin A.

[0040] Preparation Example 2 The preparation method of modified phenolic resin B is the same as that of Preparation Example 1, except that the addition amount of epichlorohydrin is 0.75 mol.

[0041] Preparation Example 3 The preparation method of modified phenolic resin C is the same as that of Preparation Example 1, except that the addition amount of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 81 g.

[0042] Preparation Example 4 The preparation method of modified phenolic resin D comprises the following steps: Q1: Mix 84 g of phenol, 48 g of formaldehyde, 100 mL of distilled water, and 3.4 g of zinc acetate dihydrate, add 6 mol / L hydrochloric acid aqueous solution to adjust the pH value to 4, and heat to 95 °C for reaction for 1.5 h to obtain a phenolic product; Q2: Mix 30 g of the phenolic product obtained in step Q1 with 2.4 g of diethoxymethylvinylsilane, heat to 95 °C for reaction for 4 h, add 6 mol / L hydrochloric acid aqueous solution to adjust the pH value to 3, add 1.5 g of boric acid, keep the temperature for reaction for 2 h, add 25 wt% sodium hydroxide aqueous solution to adjust the pH value to 5, wash twice with distilled water, carry out vacuum distillation at 170 °C for 2 h, and vacuum dry at 120 °C for 6 h to obtain modified phenolic resin D.

[0043] Preparation Example 5 The preparation method of silanized surface treatment agent A comprises the following steps: Mix 200 g of carbon nanotubes with 2000 mL of distilled water, add 70 g of vinyltriethoxysilane, and heat to 55 °C for reaction for 3 h to obtain silanized surface treatment agent A.

[0044] Preparation Example 6 The preparation method of silanized surface treatment agent B comprises the following steps: Mix 200 g of carbon nanotubes with 2000 mL of distilled water, add 140 g of vinyltriethoxysilane, and heat to 55 °C for reaction for 3 h to obtain silanized surface treatment agent B. Examples

[0045] Example 1 A preparation method of a phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction comprises the following steps: S1: Vacuum dry the modified phenolic resin A at 90 °C for 6 h, and carry out meltblowing under the conditions of a melt temperature of 140 °C, a hot air drawing temperature of 190 °C, and a receiving distance of 35 cm during drawing to obtain a meltblown material; S2: Immerse the meltblown material obtained in step S1 in the crosslinking bath at room temperature for 1.5 h, heat it from room temperature to 110 °C at a heating rate of 20 °C / h, hold the reaction for 2 h, wash it 4 times with distilled water, and dry it at 115 °C for 4 h to obtain the crosslinked material; the crosslinking bath is a composition of a 15 wt% phosphoric acid aqueous solution and a 20 wt% paraformaldehyde aqueous solution with a volume ratio of 1:1; S3: Ultrasonically immerse the crosslinked material obtained in step S2 in silanized surface treatment agent A for 20 min, add 3% by mass of benzoyl peroxide based on the mass of the crosslinked material, heat it to 75 °C, stir it at a constant temperature for 7 h, then raise the temperature to 105 °C, stir it at a constant temperature for 15 min, wash it 2 times with distilled water, and dry it at 105 °C for 4 h to obtain the meltblown nonwoven material. The thickness of the obtained meltblown nonwoven material is about 5.0 mm.

[0046] Example 2 A preparation method of a phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction, comprising the following steps: S1: Vacuum dry the modified phenolic resin A at 60 °C for 8 h, and perform meltblowing under the conditions that the melt temperature is 120 °C, the hot air drawing temperature is 170 °C, and the receiving distance during drawing is 25 cm to obtain the meltblown material; S2: Immerse the meltblown material obtained in step S1 in the crosslinking bath at room temperature for 0.5 h, heat it from room temperature to 100 °C at a heating rate of 10 °C / h, hold the reaction for 3 h, wash it 4 times with distilled water, and dry it at 105 °C for 5 h to obtain the crosslinked material; the crosslinking bath is a composition of a 15 wt% phosphoric acid aqueous solution and a 20 wt% paraformaldehyde aqueous solution with a volume ratio of 1:1; S3: Ultrasonically immerse the crosslinked material obtained in step S2 in silanized surface treatment agent A for 15 min, add 3% by mass of benzoyl peroxide based on the mass of the crosslinked material, heat it to 60 °C, stir it at a constant temperature for 8 h, then raise the temperature to 90 °C, stir it at a constant temperature for 20 min, wash it 2 times with distilled water, and dry it at 105 °C for 4 h to obtain the meltblown nonwoven material. The thickness of the obtained meltblown nonwoven material is about 5.0 mm.

[0047] Example 3 A preparation method of a phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction, comprising the following steps: S1: Vacuum dry the modified phenolic resin A at 120 °C for 4 h, and perform meltblowing under the conditions that the melt temperature is 160 °C, the hot air drawing temperature is 210 °C, and the receiving distance during drawing is 50 cm to obtain the meltblown material; S2: Immerse the meltblown material obtained in step S1 in a crosslinking bath at room temperature for 2 h, heat it from room temperature to 120 °C at a heating rate of 30 °C / h, hold the reaction for 0.5 h, wash it 4 times with distilled water, and dry it at 125 °C for 3 h to obtain a crosslinked material; the crosslinking bath is a composition of a 15 wt% phosphoric acid aqueous solution and a 20 wt% paraformaldehyde aqueous solution with a volume ratio of 1:1. S3: Ultrasonically immerse the crosslinked material obtained in step S2 in silanizing surface treatment agent A for 25 min, add benzoyl peroxide accounting for 3% of the mass of the crosslinked material, heat it to 90 °C, stir it at a constant temperature for 6 h, then raise the temperature to 120 °C, stir it at a constant temperature for 10 min, wash it 2 times with distilled water, and dry it at 105 °C for 4 h to obtain a meltblown nonwoven material. The thickness of the obtained meltblown nonwoven material is about 5.0 mm.

[0048] Example 4 A phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction and its preparation method. The specific implementation method is the same as that of Example 1, except that an equal amount of modified phenolic resin B is used to replace modified phenolic resin A.

[0049] Example 5 A phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction and its preparation method. The specific implementation method is the same as that of Example 1, except that an equal amount of modified phenolic resin C is used to replace modified phenolic resin A.

[0050] Example 6 A phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction and its preparation method. The specific implementation method is the same as that of Example 1, except that an equal amount of modified phenolic resin D is used to replace modified phenolic resin A.

[0051] Example 7 A phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction and its preparation method. The specific implementation method is the same as that of Example 1, except that an equal amount of silanizing surface treatment agent B is used to replace silanizing surface treatment agent A.

[0052] Comparative Example 1 A preparation method of a phenolic resin-based meltblown nonwoven material for sound absorption and noise reduction, which comprises the following steps: S1: Vacuum-dry modified phenolic resin A at 90 °C for 6 h, and perform meltblowing under the conditions that the melt temperature is 140 °C, the hot air drawing temperature is 190 °C, and the receiving distance during drawing is 35 cm to obtain a meltblown material. S2: Immerse the meltblown material obtained in step S1 in a crosslinking bath at room temperature for 1.5 h, heat it from room temperature to 110 °C at a heating rate of 20 °C / h, hold the reaction for 2 h, wash it 4 times with distilled water, and dry it at 115 °C for 5 h to obtain a meltblown nonwoven material. The thickness of the obtained meltblown nonwoven material is about 5.0 mm; the crosslinking bath is a composition of a 15 wt% phosphoric acid aqueous solution and a 20 wt% paraformaldehyde aqueous solution with a volume ratio of 1:1, and the thickness of the obtained meltblown nonwoven material is about 5.0 mm.

[0053] Effect evaluation: The meltblown nonwoven materials prepared in the above Examples 1-7 and Comparative Example 1 were tested and analyzed, and the specific results are shown in Table 1.

[0054] Performance test: (1) Flame retardancy test: Refer to "GB / T 5454-1997 Textiles - Test for burning performance - Oxygen index method" to determine the limiting oxygen index; a high oxygen index indicates that the material is not easily combustible, and a low oxygen index indicates that the material is easily combustible.

[0055] (2) High-temperature stability test: The thermal weight loss temperature generally refers to the temperature at which the material begins to experience significant mass loss during heating. This temperature reflects the thermal stability of the material at high temperatures. The higher the temperature at which the material remains stable at high temperatures, the more difficult it is for the material to decompose or degrade in a high-temperature environment, and thus the better its high-temperature resistance.

[0056] A STA449F3 type thermogravimetric analyzer (TG, Netzsch, Germany) was used for the thermal stability test. Under a nitrogen atmosphere, the temperature was raised from room temperature to 700 °C at a heating rate of 10 °C / min to measure the thermal weight loss temperature of the material.

[0057] (3) Sound absorption and noise reduction test: The prepared meltblown nonwoven material was statically placed in the same space for 6 months. There would be people walking around in this space and some dust would accumulate. The environmental humidity of this space was maintained at 60±5%RH and the temperature was 25±2 °C daily. The test was carried out in accordance with GB / T 18696.2-2002 "Acoustics - Measurement of sound absorption coefficient and acoustic impedance in impedance tubes - Part 2: Transfer function method".

[0058] Table 1 Serial number Limiting oxygen index Thermogravimetric temperature / °C Sound absorption coefficient (below 150 HZ) Example 1 37 585 0.91 Example 2 35 570 0.85 Example 3 36 580 0.89 Example 4 33 570 0.89 Example 5 32 570 0.89 Example 6 30 550 0.88 Example 7 36 560 0.81 Comparative example 1 36 545 0.72 From the results in Table 1, it can be seen that the meltblown nonwoven materials prepared in Examples 1-3 have good flame retardancy and high-temperature resistance, and the sound absorption and noise reduction effect is still excellent after being placed for 6 months.

[0059] Compared with Example 1, in the preparation of modified phenolic resin in Examples 4-6, in Example 4, the molar ratio of resorcinol to epichlorohydrin was changed, resulting in a decrease in phenolic hydroxyl groups, which was not conducive to the formation of phenolic aldehyde products in step S2. In Example 5, the mass ratio of phenolic aldehyde products to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was changed, and the introduced phosphorus-containing groups were reduced. In Example 6, no epoxy groups and phosphorus-containing groups that could combine were introduced. As a result, they would all affect the high-temperature resistance and flame retardancy of phenolic resin.

[0060] In Example 7, compared with Example 1, the mass ratio of carbon nanotubes to vinyltriethoxysilane was changed during the preparation of the surface treatment agent, resulting in a reduction in the carbon nanotubes crosslinked on the surface layer of the meltblown nonwoven material, thereby affecting the antistatic ability. In Comparative Example 1, compared with Example 1, the material was not further treated with the surface treatment agent. After standing for 6 months, particulate dust was adsorbed on the surface layer of the meltblown nonwoven material due to electrostatic action, thus blocking the pores and leading to a decrease in the sound absorption effect of Example 7 and Comparative Example 1.

[0061] As mentioned above, the above are only preferred embodiments of the present invention and do not impose any form of limitation on this application. Although this application is disclosed with preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art, without departing from the scope of the technical solution of this application, making some changes or modifications using the technical content disclosed above is equivalent to equivalent implementation cases. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution.

Claims

1. A method for preparing a phenolic resin-based melt-blown nonwoven material for sound absorption and noise reduction, characterized in that: The following steps are included: S1: vacuum drying the modified phenolic resin and then melt-blowing it to obtain a melt-blown material; S2: immersing the melt-blown material in a cross-linking bath, curing by heating, washing, and drying to obtain a cross-linked material; S3: ultrasonically immersing the cross-linked material in a silanized surface treatment agent, and drying to obtain a melt-blown nonwoven material.

2. The method for preparing a phenolic resin-based melt-blown nonwoven material for sound absorption and noise reduction according to claim 1, characterized in that In step S1, the vacuum drying condition is vacuum drying at 60-120°C for 4-8h; the working conditions of the melt blowing are melt temperature of 120-160°C, hot air drawing temperature of 170-210°C, and receiving distance during drawing of 25-50cm; The preparation method of the modified phenolic resin comprises the following steps: Q1: Mix resorcinol and sodium hydroxide aqueous solution, heat to 70-80°C, stir and react for 30-40 minutes, add epichlorohydrin dropwise, add sodium hydroxide aqueous solution dropwise to adjust the pH value to 9-10, stir and react at constant temperature for 1-2 hours, cool to -3-4°C, adjust the pH to neutral, and obtain a phenolic compound; Q2: mixing the phenolic compound with phenol, an aldehyde compound, and a divalent metal salt to carry out a polycondensation reaction to obtain a phenolic product; Q3: Mixing the phenolic product with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heating to 160-170° C. for reaction for 6-8 hours, cooling to 65-75° C., and dehydrating to obtain a phosphorus-containing phenolic resin compound; Q4: Mix the phosphorus-containing phenolic resin compound with silicone, heat to 90-110°C for reaction for 3-4 hours, adjust the pH value to 2.5-3.5, add boric acid, keep warm for reaction for 2-2.5 hours, adjust the pH value to 5-5.5, wash, distill under reduced pressure, and dry to obtain a modified phenolic resin.

3. The method for preparing a phenolic resin-based melt-blown nonwoven material for sound absorption and noise reduction according to claim 2, characterized in that In step Q1, the molar ratio of resorcinol to epichlorohydrin is 1:(0.95~1.15).

4. The method for preparing a phenolic resin-based melt-blown nonwoven material for sound absorption and noise reduction according to claim 2, characterized in that In step Q2, the mass ratio of the phenolic compound, phenol, and aldehyde compound is (0.25-0.55):1:(0.6-1); the aldehyde compound is formaldehyde; and the divalent metal salt is zinc acetate.

5. The method for preparing a phenolic resin-based melt-blown nonwoven material for sound absorption and noise reduction according to claim 2, characterized in that In step Q3, the mass ratio of the phenolic product to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(3-5).

6. The method for preparing a phenolic resin-based melt-blown nonwoven material for sound absorption and noise reduction according to claim 2, characterized in that In step Q4, the mass ratio of the phosphorus-containing phenolic resin compound, the organosilicon, and the boric acid is 1:(0.06-0.1):(0.04-0.06); the organosilicon is diethoxymethylvinylsilane.

7. The method for preparing a phenolic resin-based melt-blown nonwoven material for sound absorption and noise reduction according to claim 1, characterized in that The specific steps of step S2 are: The melt-blown material is immersed in a cross-linking bath at room temperature for 0.5-2 hours, heated from room temperature to 100-120° C. at a heating rate of 10-30° C. / h, kept warm for 0.5-3 hours, washed with distilled water 4 times, and dried at 105-125° C. for 3-5 hours to obtain a cross-linked material; The cross-linking bath is a composition of an acid solution and a trioxymethylene solution; in the composition, the volume ratio of the acid solution to the trioxymethylene solution is 1:1; The mass fraction of the acid solution is 10-25wt%; the acid solution is any one or more of hydrochloric acid solution, phosphoric acid solution, oxalic acid solution, and sulfuric acid solution; The mass fraction of the trioxymethylene solution is 10-25wt%.

8. The method for preparing a phenolic resin-based melt-blown nonwoven material for sound absorption and noise reduction according to claim 1, characterized in that The specific steps of step S3 are: The cross-linked material is ultrasonically immersed in a silanized surface treatment agent for 15 to 25 minutes, an initiator is added, the material is heated to 60 to 90° C., stirred at a constant temperature for 6 to 8 hours, then heated to 90 to 120° C., stirred at a constant temperature for 10 to 20 minutes, washed, and dried to obtain a melt-blown nonwoven material.

9. The method for preparing a phenolic resin-based melt-blown nonwoven material for sound absorption and noise reduction according to claim 8, characterized in that The amount of the initiator is 3% of the cross-linking material; the initiator is benzoyl peroxide; The preparation method of the silanized surface treatment agent is as follows: mixing carbon nanotubes with distilled water, adding vinyl triethoxysilane, heating to 45-65°C for reaction for 2-4 hours, and obtaining the silanized surface treatment agent; the mass ratio of the carbon nanotubes to vinyl triethoxysilane is 1:(0.2-0.5).

10. A phenolic resin-based melt-blown nonwoven material obtained by the preparation method according to any one of claims 1 to 9.