A method for preparing low-frequency sound-absorbing functional nanofiber for high-end equipment

Abstract

The present invention relates to the field of new materials, and discloses a method for preparing a low-frequency band sound-absorbing functional nanofiber for high-end equipment. The method includes: adding diisopropylamine peroxide or hyperbranched polyester to a first polymer resin to prepare a first spinning solution, so that the dynamic viscosity of the first spinning solution at 300 degrees Celsius is 1-10Pa·s; melt-blowing equipment is used to melt-blown the first spinning solution to obtain a first polymer fiber; decalin is added to a second polymer resin to prepare a second spinning solution, so that the dynamic viscosity of the second spinning solution at 140 degrees Celsius is 10-50mPa·s, and a flash evaporation device is used to flash-evaporate the second spinning solution to obtain a second polymer fiber; under the traction of a fan, the first polymer fiber at the outlet of the melt-blown device and the second polymer fiber at the outlet of the flash evaporation device are mixed evenly using multiple air nozzles to obtain low-frequency band sound-absorbing functional nanofibers. The preparation method of the present invention is simple and has better sound absorption effect.

Description

Technical Field

[0001] The present invention relates to the field of new materials, and in particular to a method for preparing low- and medium-frequency-band sound-absorbing functional nanofibers for high-end equipment. Background Art

[0002] So far, porous fibers and foam materials such as PP, PET, polyurethane and glass fiber are the most representative and widely used sound-absorbing materials we know. Since most of the above materials are at the micron level, there are few application scenarios for nano-level fibers below 1 micron, so the application effect and sound absorption and sound insulation capabilities are also greatly limited.

[0003] In addition, according to the analysis results based on Biot theory, in order to effectively absorb sound waves in various frequency bands, the size and complexity of the holes in the porous structure of the sound-absorbing material, as well as the distance between the holes are very important indicators.

[0004] Therefore, in order to absorb sound waves of various frequencies, using coarse fibers of several microns as the skeleton to maintain the overall elasticity, while using nano-level ultra-fine fibers to fill the porous structure to increase the surface area and complexity of the material has been proven to be a very effective method. However, the manufacturing process of this material is very complicated. Summary of the invention

[0005] The main purpose of the present invention is to solve the problem of the complexity of the method of preparing low-frequency sound-absorbing functional nanofibers for high-end equipment in the prior art. In the first aspect of the present invention, a method for preparing low-frequency sound-absorbing functional nanofibers for high-end equipment is provided, the method comprising:

[0006] Adding diisopropylamine peroxide or hyperbranched polyester to a first polymer resin to prepare a first spinning solution, so that the kinematic viscosity of the first spinning solution at 300 degrees Celsius is 1-10 Pa·s;

[0007] Using a melt-blowing device to melt-blown the first spinning solution to obtain a first polymer fiber;

[0008] Adding decahydronaphthalene to the second polymer resin to prepare a second spinning solution, so that the dynamic viscosity of the second spinning solution at 140 degrees Celsius is 10-50 mPa·s,

[0009] flash evaporation equipment is used to flash evaporate the second spinning solution to obtain a second polymer fiber;

[0010] Under the traction of a fan, the first polymer fibers at the outlet of the melt-blowing device and the second polymer fibers at the outlet of the flash evaporation device are evenly mixed using multiple air nozzles to obtain medium and low frequency band sound-absorbing functional nanofibers.

[0011] As a preferred technical solution, the parameters of the meltblowing equipment are adjusted so that the average fiber diameter of the second polymer fibers is normally distributed.

[0012] As a preferred technical solution, after the fan is pulled, the wind speed at the outlet of the meltblowing equipment and the outlet of the flash evaporation equipment is 100-400m / s.

[0013] As a preferred technical solution, the distance between the meltblowing equipment outlet and the air nozzle is 1-3 mm.

[0014] As a preferred technical solution, the distance between the flash evaporation equipment outlet and the air nozzle is 1-3 mm.

[0015] As a preferred technical solution, the angle formed by the outlet of the meltblowing equipment and the air nozzle is 30-50 degrees.

[0016] As a preferred technical solution, the angle formed by the outlet of the flash evaporation equipment and the air nozzle is 30-50 degrees.

[0017] A preparation system for low- and medium-frequency sound-absorbing functional nanofibers for high-end equipment, the preparation system comprising a melt-blowing device, a flash evaporation device, a plurality of air spray holes, a fan and a cord fabric;

[0018] The melt-blowing device is used to melt-blown the first spinning solution to obtain the first polymer fiber;

[0019] The flash evaporation device is used to flash evaporate the second spinning solution to obtain a second polymer fiber;

[0020] The plurality of air nozzles are used to mix the first polymer fibers and the second polymer fibers;

[0021] At least one air spray hole is provided at the outlet of the melt-blowing equipment;

[0022] At least one air spray hole is arranged at the outlet of the flash evaporation equipment;

[0023] The fan is used to pull the first polymer fiber and the second polymer fiber, and pull the first polymer fiber and the second polymer fiber to the cord fabric to obtain medium and low frequency band sound-absorbing functional nanofibers.

[0024] The present invention achieves sound wave absorption across multiple frequency bands and enhances the absorption performance in the medium and low frequency bands by adopting the preparation system of the present invention, and designs a structure combining several micron coarse fibers (as a skeleton to ensure overall elasticity) and nanometer-scale fine fibers (for filling porous structures). This design is intended to increase the internal surface area of ​​the material, thereby deepening the penetration of sound waves in its pores. The pores, especially the open and interconnected pores, subject the sound waves to the friction and viscous resistance of the air molecules and induce the mechanical vibration of the fiber, thereby realizing the conversion of sound energy into heat energy. When sound interacts with the material, part of the sound energy will be reflected and part will penetrate the material. In addition, due to the vibration of the material or the propagation of sound inside it, the sound energy generates friction with the surrounding medium and is converted into heat energy. Through the flash spraying method developed in this project, the fiber ratio and porosity can be accurately controlled, and the surface area and structural complexity inside the fiber can be further optimized to maximize the friction effect between the sound and the material and achieve excellent sound absorption performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the preparation system of the functional nanofibers for sound absorption in the medium and low frequency bands of the present invention.

[0026] Figure 2 The following are the SEM micrographs and the degree distribution diagram of the fibers prepared in Example 1.

[0027] Figure 3 These are the sound absorption rates of the fiber assembly prepared in Example 1 at 0-5000 Hz and 0-1000 Hz.

[0028] Figure 4 The following are the SEM micrographs and degree distribution diagrams of the fibers prepared in Example 2.

[0029] Figure 5 These are the sound absorption rates of the fiber assembly prepared in Example 2 at 0-5000 Hz and 0-1000 Hz.

[0030] Figure 6 The following are the SEM micrographs and degree distribution diagrams of the fibers prepared in Example 3.

[0031] Figure 7 These are the sound absorption rates of the fiber assembly prepared in Example 3 at 0-5000 Hz and 0-1000 Hz.

[0032] Reference numerals:

[0033] Melt-blowing equipment 1, flash evaporation equipment 2, air spray holes 3, fans 4, and cord fabrics 5. DETAILED DESCRIPTION

[0034] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" or "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or production equipment that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or production equipment.

[0035] like Figure 1 , a preparation system of low- and medium-frequency sound-absorbing functional nanofibers for high-end equipment, the preparation system comprising a melt-blowing device, a flash evaporation device, a plurality of air nozzles, a fan and a cord fabric; the melt-blowing device is used to perform melt-blowing treatment on a first spinning solution to obtain a first polymer fiber; the flash evaporation device is used to perform flash evaporation treatment on a second spinning solution to obtain a second polymer fiber; the plurality of air nozzles are used to mix the first polymer fiber and the second polymer fiber; at least one air nozzle is provided at the outlet of the melt-blowing device; at least one air nozzle is provided at the outlet of the flash evaporation device; the fan is used to pull the first polymer fiber and the second polymer fiber, and pull the first polymer fiber and the second polymer fiber to the cord fabric to obtain low- and medium-frequency sound-absorbing functional nanofibers.

[0036] 1. Meltblowing method: Pour the selected modified high-fluidity polymer material into a screw machine, heat it to more than 1.5 times its melting point, and extrude it from the die head while being instantly stretched into fibers by the high-temperature sonic air flowing out of the wind knife. Since the flow velocity distribution and temperature distribution of the wind knife are improved, the fibers flowing out from various places will be stretched into fiber aggregates of varying thicknesses with normal distribution.

[0037] 2. Flash evaporation method: Put the selected polymer material into the solvent in a certain proportion, heat and stir until dissolved, and then put it into the equipment to fiberize it. Similarly, based on the position adjustment of the die head and air and the control of the air flow rate distribution and temperature distribution, a fiber assembly with normal distribution and different thicknesses can be made. The combined use of 1 and 2 is called the flash evaporation method.

[0038] The average fiber diameter of the flash-blown fibers was 5-8 μm and had a normal fiber diameter distribution. The apparent density was adjusted to 0.05 g / cm 3 When (porosity = 1-(apparent density / material density)) is below, the fiber assembly will have the following performance parameters:

[0039] Porosity:>95%

[0040] Lost degree: 1-1.4

[0041] Sound absorption rate of 200-400Hz: ≥50%

[0042] Sound absorption rate of 400-800Hz: ≥90%

[0043] 800-5000Hz sound absorption rate ≥95%

[0044] (Note 1: Rail transit (tire noise) tire noise frequency range → 500-2000Hz)

[0045] (Note 2: High-end equipment (machine) frequency range → 200 or more)

[0046] Longitudinal elastic modulus>10KPa

[0047] Average fiber diameter: 5-8 microns

[0048] Fiber diameter distribution: Normal distribution

[0049] Coefficient of variation: 45%-65%

[0050] Average sound absorption coefficient above 400Hz: ≥0.8

[0051] Fluid resistance: >10000Ns / m^4.

[0052] The parameters of the flash evaporation device are adjusted so that the average fiber diameter of the first polymer fiber is normally distributed.

[0053] If the material used is a corrosion-resistant, high-temperature-resistant polymer material, the fiber assembly will also have the following properties.

[0054] Acid and alkali resistant, organic solvent resistant

[0055] Water absorption: strong hydrophobicity

[0056] Antibacterial effect: JIS1902:2015 activity value 2.8 (good effect)

[0057] A method for preparing low- and medium-frequency sound-absorbing functional nanofibers for high-end equipment, the method comprising:

[0058] Adding diisopropylamine peroxide to a first polymer resin to prepare a first spinning solution, so that the kinematic viscosity of the first spinning solution at 300 degrees Celsius is 1-10 Pa·s;

[0059] Using a melt-blowing device to melt-blown the first spinning solution to obtain a first polymer fiber;

[0060] Adding decalin to the second polymer resin to prepare a second spinning solution, so that the dynamic viscosity of the second spinning solution at 140 degrees Celsius is 10-50 mPa·s;

[0061] flash evaporation equipment is used to flash evaporate the second spinning solution to obtain a second polymer fiber;

[0062] Under the traction of a fan, the first polymer fibers at the outlet of the melt-blowing device and the second polymer fibers at the outlet of the flash evaporation device are evenly mixed using multiple air nozzles to obtain medium and low frequency band sound-absorbing functional nanofibers.

[0063] As a preferred embodiment, the parameters of the flash evaporation equipment are adjusted so that the average fiber diameter of the first polymer fiber is normally distributed.

[0064] As a preferred embodiment, the parameters of the meltblowing equipment are adjusted so that the average fiber diameter of the second polymer fibers is normally distributed.

[0065] As a preferred embodiment, after the fan is pulled, the wind speed at the outlet of the meltblowing equipment and the outlet of the flash evaporation equipment is 100-400m / s.

[0066] As a preferred embodiment, the distance between the meltblowing equipment outlet and the air nozzle is 1-3 mm.

[0067] As a preferred embodiment, the distance between the flash evaporation equipment outlet and the air nozzle is 1-3 mm.

[0068] As a preferred embodiment, the angle formed by the outlet of the meltblowing equipment and the air nozzle is 30-50 degrees.

[0069] As a preferred embodiment, as a preferred embodiment, the angle formed by the outlet of the flash evaporation equipment and the air nozzle is 30-50 degrees.

[0070] In order to prevent high-temperature carbonization during melt-blown fiber production, the equipment we developed uses a short screw machine with an aspect ratio of no more than 24 to melt and extrude the material. In order to completely melt the material in a short time, microparticles with a particle size of less than 2mm are selected.

[0071] Example 1

[0072] Polypropylene (Basel MF650Y) is used as a polymer resin, and diisopropylamine peroxide is added to prepare a first spinning solution, so that the dynamic viscosity of the first spinning solution at 300 degrees Celsius is 8 Pa·s; polypropylene is used as a polymer resin, and decalin is added to prepare a second spinning solution, so that the dynamic viscosity of the second spinning solution at 140 degrees Celsius is 30 mPa·s;

[0073] The parameters of the flash evaporation device are adjusted so that the average fiber diameter of the first polymer fiber is normally distributed. The parameters of the melt-blowing device are adjusted so that the average fiber diameter of the second polymer fiber is normally distributed. The wind speed at the outlet of the melt-blowing device and the outlet of the flash evaporation device is 300 m / s. The distance between the outlet of the melt-blowing device and the air nozzle is 2 mm, and the angle is 40 degrees. The distance between the outlet of the flash evaporation device and the air nozzle is 2 mm, and the angle is 40 degrees.

[0074] The above equipment was used to process the low- and medium-frequency sound-absorbing functional nanofibers. 100 fiber samples were taken, with an average fiber diameter of 7.5, a standard deviation of 2.3, and a fiber apparent density of 0.03 g / cm 3 The average fiber spacing is about 30 μm. The experimental results are as follows Figure 2 and Figure 3 .

[0075] Example 2

[0076] PET (kuraray Ks710B-8S) is used as a polymer resin, and hyperbranched polyester (Weihai Chenyuan Molecular CYD-C602A) is added to prepare a first spinning solution, so that the dynamic viscosity of the first spinning solution at 300 degrees Celsius is 7Pa·s; polypropylene is used as a polymer resin, and decalin is added to prepare a second spinning solution, so that the dynamic viscosity of the second spinning solution at 140 degrees Celsius is 40mPa·s;

[0077] The parameters of the flash evaporation device are adjusted so that the average fiber diameter of the first polymer fiber is normally distributed. The parameters of the melt-blowing device are adjusted so that the average fiber diameter of the second polymer fiber is normally distributed. The wind speed at the outlet of the melt-blowing device and the outlet of the flash evaporation device is 300 m / s. The distance between the outlet of the melt-blowing device and the air nozzle is 2 mm, and the angle is 40 degrees. The distance between the outlet of the flash evaporation device and the air nozzle is 2 mm, and the angle is 40 degrees.

[0078] The above-mentioned equipment was used to process the low- and medium-frequency sound-absorbing functional nanofibers. 100 fiber samples were taken, with an average fiber diameter of 7.8, a standard deviation of 2.6, and a fiber apparent density of 0.03 g / cm 3 The average fiber spacing is about 30 μm. The experimental results are as follows Figure 4 and Figure 5 .

[0079] Example 3

[0080] PC (IDEMITSU MD1500) is used as a polymer resin, and hyperbranched polyester (Weihai Chenyuan Molecular CYD-C602A) is added to prepare a first spinning solution, so that the dynamic viscosity of the first spinning solution at 300 degrees Celsius is 5Pa·s; polypropylene is used as a polymer resin, and decalin is added to prepare a second spinning solution, so that the dynamic viscosity of the second spinning solution at 140 degrees Celsius is 20mPa·s;

[0081] The parameters of the flash evaporation device are adjusted so that the average fiber diameter of the first polymer fiber is normally distributed. The parameters of the melt-blowing device are adjusted so that the average fiber diameter of the second polymer fiber is normally distributed. The wind speed at the outlet of the melt-blowing device and the outlet of the flash evaporation device is 300 m / s. The distance between the outlet of the melt-blowing device and the air nozzle is 2 mm, and the angle is 40 degrees. The distance between the outlet of the flash evaporation device and the air nozzle is 2 mm, and the angle is 40 degrees.

[0082] The above-mentioned equipment was used to process the low- and medium-frequency sound-absorbing functional nanofibers. 100 fiber samples were taken, with an average fiber diameter of 8.2, a standard deviation of 3.1, and a fiber apparent density of 0.03 g / cm 3 , the average fiber spacing is about 30 μm, and the experimental results are as follows Figure 6 and Figure 7 .

[0083] It can be seen that the low-frequency sound-absorbing functional nanofibers prepared by the above scheme have good quality, and the preparation method is simple and convenient. Compared with conventional products (prepared separately by flash evaporation equipment or melt-blown equipment), the low-frequency sound-absorbing functional nanofibers prepared by the preparation method of the present invention have the following indicators:

[0084]

[0085]

[0086] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing low-frequency and medium-frequency sound-absorbing functional nanofibers for high-end equipment, characterized in that: The preparation method comprises: Adding diisopropylamine peroxide or hyperbranched polyester to the first polymer resin to prepare a first spinning solution, so that the kinematic viscosity of the first spinning solution at 300 degrees Celsius is 1-10 Pa·s; Using a melt-blowing device to melt-blown the first spinning solution to obtain a first polymer fiber; Decalin is added to the second polymer resin to prepare a second spinning solution, so that the dynamic viscosity of the second spinning solution is 10-50 mPa·s at 140 degrees Celsius. flash evaporation equipment is used to flash evaporate the second spinning solution to obtain a second polymer fiber; Under the traction of a fan, the first polymer fiber at the outlet of the melt-blowing device and the second polymer fiber at the outlet of the flash evaporation device are uniformly mixed by using multiple air nozzles to obtain medium and low frequency band sound-absorbing functional nanofibers; The preparation system adopted by the preparation method includes a melt-blowing device, a flash evaporation device, a plurality of air spray holes, a fan and a cord fabric; the plurality of air spray holes are arranged between the outlet of the melt-blowing device and the flash evaporation device and the cord fabric; The melt-blowing device is used to melt-blown the first spinning solution to obtain the first polymer fiber; The flash evaporation device is used to flash evaporate the second spinning solution to obtain a second polymer fiber; The plurality of air nozzles are used to mix the first polymer fibers and the second polymer fibers; At least one air spray hole is provided at the outlet of the melt-blowing equipment; At least one air spray hole is arranged at the outlet of the flash evaporation equipment; adjusting the parameters of the flash evaporation device so that the average fiber diameter of the first polymer fiber is normally distributed; Adjusting the parameters of the meltblowing device so that the average fiber diameter of the second polymer fiber is normally distributed; The fan is used to pull the first polymer fiber and the second polymer fiber, and pull the first polymer fiber and the second polymer fiber to the cord fabric to obtain the functional nanofibers with sound absorption in the medium and low frequency bands; The parameters of the low- to medium-frequency sound-absorbing functional nanofibers are: The apparent density is 0.05 g / cm 3 the following; Average fiber diameter: 5-8 microns; Porosity>95%; The wind speed at the outlet of the melt-blowing equipment and the outlet of the flash evaporation equipment is 100-400m / s; The distance between the melt-blowing equipment outlet and the air spray hole is 1-3 mm; The distance between the flash evaporation equipment outlet and the air spray hole is 1-3 mm; The angle formed by the outlet of the melt-blowing equipment and the air nozzle is 30-50 degrees; The angle formed by the outlet of the flash evaporation equipment and the air spray hole is 30-50 degrees.

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