CN219903612U - Broadband noise reduction structure of composite expanded graphite from low frequency to high frequency - Google Patents
Broadband noise reduction structure of composite expanded graphite from low frequency to high frequency Download PDFInfo
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- CN219903612U CN219903612U CN202220238166.7U CN202220238166U CN219903612U CN 219903612 U CN219903612 U CN 219903612U CN 202220238166 U CN202220238166 U CN 202220238166U CN 219903612 U CN219903612 U CN 219903612U
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Abstract
The utility model discloses a broadband noise reduction structure of composite expanded graphite from low frequency to high frequency, which is a sandwich structure of a multi-layer honeycomb with a skin, wherein a micro-pore plate is adopted between every two layers of honeycomb of the sandwich structure of the multi-layer honeycomb with the skin and one side facing noise is bonded through damping glue, the sandwich structure of the multi-layer honeycomb with the skin is filled with a composite foam material of the expanded graphite and resin, and the non-noise facing side of the sandwich structure of the multi-layer honeycomb with the skin is a substrate without micropores. The product production process and the product are environment-friendly, have the advantages of high mechanical strength, low density, long service life, high temperature resistance, flame retardance and the like, and solve the defects of poor low-frequency performance, insufficient bandwidth, low strength, inflammability of foam and the like of the sound absorption and noise reduction material.
Description
Technical Field
The utility model belongs to the field of sound-absorbing and noise-reducing materials, and particularly relates to a broadband noise-reducing structure of composite expanded graphite from low frequency to high frequency.
Background
Noise becomes one of three nuisance in the process of urbanization and industrialization, and people living and working near the noise source are greatly injured by the noise. Noise sources can be subjected to noise reduction treatment through shielding, absorption, attenuation and the like, noise sources with openness need to be subjected to noise reduction through absorption, such as operation noise of highways, high-speed rails and the like, different noise sources are different in frequency, intensity and direction, and the optimal noise reduction method is different, but low-frequency and broadband noise reduction needs high-cost and thicker materials and structures to be subjected to attenuation, so that the noise reduction method is a great challenge for large-area application of noise reduction materials.
Noise reduction materials are generally multi-layer cavity structures and fall into two main categories: the Xin Mhuo-z resonator is of a typical resonance type and is of a porous material type, the air flow loss of the microporous resonance plate is utilized for absorbing waves, damping materials can be coated on the surface of the resonance plate to increase the wave absorption, the design is simple in structure, low-frequency noise reduction is easy to realize, but the bandwidth is required to be expanded through a multi-layer structure design. The porous material attenuates noise through vibration loss of the material and viscous friction loss with air, and generally has good high-frequency sound absorption effect. The porous material is divided into an open-cell material, a closed-cell material and a half-cell material, wherein the loss of the half-cell material is the largest, the related loss mechanism is more complex, the structure of the half-cell material is close to the closed-cell material, and micropore connection is arranged between every two air cavities, which is similar to a micropore resonance plate, so that noise loss is increased.
The rigidity of the graphene, mica and other two-dimensional materials in the high polymer composite material is far higher than that of the base material, so that the graphene, mica and other two-dimensional materials play a role of a resonance loss plate in the composite material. The graphene aerogel realizes higher noise reduction under the condition of very low density, and the density is lower than 0.1g/cm 3 Even below 0.01g/cm 3 The microcosmic appearance is a semi-open porous material, the micropore size is much smaller than that of the foaming sponge, the specific surface area is much larger, each gram is tens and hundreds of square meters, and the sponge is a plurality of square meters. The noise reduction mechanism is similar to that of half-open cell foam, but the efficiency is higher, and particularly, the performance improvement of low frequency is larger. The low density graphene aerogel has low stiffness and requires a hollow structural material to provide structural strength and stiffness, such as a honeycomb core. The production process of the low-density graphene aerogel needs freeze drying, so that the production efficiency is extremely low, the production cost is extremely high, and the large-scale application is difficult to realize.
Disclosure of Invention
The utility model provides a multi-layer broadband noise reduction structure from low frequency to high frequency, which has the advantages of environment-friendly production process and product, high mechanical strength, lower density, long service life, high temperature resistance, flame retardance and the like, and solves the defects of poor low-frequency performance, insufficient bandwidth, low strength, inflammable foam and the like of a sound absorption noise reduction material. The specific scheme is as follows:
the utility model provides a broadband noise reduction structure of composite expanded graphite from low frequency to high frequency, which is a sandwich structure of a multi-layer honeycomb with a skin, wherein a micro-pore plate is adopted between every two layers of honeycomb of the sandwich structure of the multi-layer honeycomb with the skin and one side facing noise is bonded through damping glue, the sandwich structure of the multi-layer honeycomb with the skin is filled with a composite foam material of the expanded graphite and resin, and the non-noise facing side of the sandwich structure of the multi-layer honeycomb with the skin is a substrate without micropores.
Optionally, the audio impedance and the loss of each layer of the sandwich structure of the multilayer honeycomb with the skin are regulated and controlled by the size of the honeycomb, the filling density of the composite material of the expanded graphite and the resin, and the material selection, the thickness, the aperture and the number of the micropore plates;
the sound impedance range of the multilayer honeycomb sandwich structure with the skin is 3 multiplied by 10 3 ～2×10 6 kg/m 2 S, the impedance of the honeycomb layer close to the noise side is the lowest, the impedance of each layer increases along with the increase of the distance from the sound source, so that the honeycomb layer is combined to form a broadband noise reduction structure, and the noise reduction frequency is from 10Hz to 20kHz.
Optionally, the honeycomb wall material of the multilayer honeycomb sandwich structure with the skin is at least one of aluminum foil, stainless steel foil, kraft paper, aramid paper, glass fiber composite material, glass fiber paper and plastic, and the density of the honeycomb of the multilayer honeycomb sandwich structure with the skin is 10-200g/m 2 The aperture is 3-50 mm or the side length is 1.8-30 mm, and the thickness is 2-100 mm.
Optionally, the sandwich structure of the multilayer honeycomb with the skin adopts kraft paper honeycomb, the aperture is 10-50 mm or the side length is 5.5-30 mm, the thickness is 5-100 mm, and the honeycomb section comprises at least one of a hexagon, a rectangle formed by stretching the hexagon, a square formed by mutually embedding flat plates and a rectangle formed by mutually embedding flat plates;
the kraft paper honeycomb is subjected to resin solution impregnation treatment, wherein the impregnating resin is at least one of phenolic resin, epoxy resin and vinyl resin, and the concentration of the impregnating resin is 5-30%.
Optionally, the material of the micro-pore plate is glass fiber reinforced composite material, plastic or metal, the thickness is 0.1-2 mm, the aperture is 0.02-2 mm, and the aperture ratio is 1% -10%;
damping glue is adopted when the micro-pore plate is glued with the honeycomb, the damping factor of the damping glue is higher than 0.2, the bonding strength is higher than 5MPa, and glass fiber reinforced vinyl resin composite material is selected as the base material of the micro-pore plate.
Optionally, the composite foam material with the porous expanded graphite and the resin is filled in the multilayer honeycomb sandwich structure with the skin, and the density of the filled material is 0.005-0.5 g/cm 3 ；
The expanded graphite is prepared by high-temperature expansion of expandable graphite, the volume expansion multiple of the expanded graphite after heating is 100-800 times, and the specific surface area is better than 20m 2 /g；
The resin is at least one of epoxy, polyurethane, synthetic rubber solution, synthetic latex emulsion and natural latex emulsion, the resin can be atomized and mixed with graphite worms, and the weight ratio of the graphite worms to the resin is 100:10 to 500.
Optionally, the substrate is made of metal with high acoustic resistance, and is glued with the honeycomb layer by using damping glue.
The utility model also provides a manufacturing method of the composite expanded graphite noise reduction structure from low frequency to high frequency, which comprises the following steps:
s1, determining structural characteristics of a multilayer honeycomb sandwich structure, characteristics of a filled expanded graphite composite foam material and sizes and numbers of micro holes by using finite element simulation software;
s2, stretching the honeycomb blocks by using a stretcher, fixing the honeycomb blocks on a tooling bracket, immersing the honeycomb blocks in a resin solution tank for 2-5 minutes, taking out the honeycomb blocks, drying the honeycomb blocks by using warm air, and curing the honeycomb blocks in a baking oven at 120 ℃;
s3, expanding expandable graphite in a high-temperature furnace according to the characteristics of the filled expanded graphite composite foam material to obtain graphite worms;
s4, mixing the graphite worms with resin according to the characteristics of the filled expanded graphite composite foam material, and spraying the resin into the worms in stirring by adopting a resin atomization process;
s5, filling the mixture of the graphite worms and the resin into a honeycomb fixed in a die according to the design amount, and carrying out hot press shaping by a hot press;
s6, punching the micro-pore plate according to the design, wherein the punching method adopts laser, punching or hot-pressing punching, or adopts the material with holes to manufacture the micro-pore plate, the damping glue is coated, the damping glue blocking the micro-pores is blown open by adopting high-pressure air flow, or the laser is used for punching holes after the damping glue is coated so as to lead the blocked micro-pores to be opened;
s7, combining each layer of honeycomb with the micro-pore plate coated with the damping gel, the skin and the substrate as required, and adopting a hot press to perform hot-pressing and bonding to form a whole, thereby obtaining the composite expanded graphite broadband noise reduction structure from low frequency to high frequency.
Optionally, in step S3: producing graphite worms by adopting continuous process equipment, wherein the continuous process equipment comprises a high-temperature furnace;
in the step S3, expandable graphite is specifically introduced from the upper part of the high-temperature furnace, and graphite worms are collected from the bottom; or, introducing expandable graphite into the high-temperature air flow of the high-temperature furnace, and collecting graphite worms after cooling along with the air flow; an electrothermal converter is adopted to expand expandable graphite, and the inclination angle of the converter is 30-70 degrees.
Optionally, the mixing process of the graphite worms and the resin adopts a heated spiral ribbon stirring kettle, the heating temperature is 30-80 ℃, and the solvent in the resin is dried.
Specifically, the composite expanded graphite noise reduction structure from low frequency to high frequency adopts a multi-layer paper honeycomb sandwich structure, has low audio impedance, is easy to realize impedance matching, adopts micro-pore plates and damping glue to bond each layer of honeycomb, namely increases bonding strength and loss factors, fills half-open expanded graphite worm resin composite materials with different densities into the honeycomb, increases loss factors with different mechanisms, and adopts graphite worms as open pore materials, thereby reducing porosity and aperture ratio and increasing audio impedance through compaction, and addingThe resin can increase strength and audio impedance, reduce aperture ratio, and has very low density of graphite worms compared with graphene aerogel, specific surface area per gram is over 30 square meters, even 70 square meters, and the wall thickness of foam is only about 10 nanometers compared with materials such as sponge foam, and the cost is low, and the large-scale production process is mature. The multi-mechanism noise reduction is adopted, the acoustic impedance and the loss of each layer of the multi-layer honeycomb sandwich structure can be regulated and controlled by the size of a honeycomb, the filling density of a composite material of expanded graphite and resin, the material selection, the thickness, the aperture and the number of the micropore plates, the acoustic impedance range of the honeycomb sandwich structure is 3x10 3 ～2x10 6 kg/m 2 S, the impedance of the honeycomb layer close to one side of noise is the lowest, the audio impedance of each layer is increased along with the increase of the distance from the sound source, so that the honeycomb layer is combined to form a broadband noise reduction structure, the noise reduction frequency is from 10Hz to 20kHz, low-frequency and broadband noise reduction is realized with lower thickness, and the design can be optimized by adopting finite element simulation software. Compared with polyurethane and other foaming materials added by graphene and graphite nano-sheets, the weight proportion of the graphite can be higher than 50% of the total weight of foam, and the proportion of the foam graphite added by the graphene is less than 10%, so that the modulus is lower at low density, and the noise reduction effect is lower.
In one specific embodiment, the honeycomb wall material is at least one of aluminum foil, stainless steel foil, kraft paper, aramid paper, glass fiber composite material, glass fiber paper, plastic and the like, and the density of the honeycomb is 10-200g/m 2 The aperture is 3-50 mm, and the thickness is 2-100 mm. The aluminum foil and stainless steel foil honeycomb has high heat-resistant temperature, high cost, high specific strength of aramid paper and glass fiber composite material, but also high cost, poor flame retardance and heat resistance of plastic honeycomb, high honeycomb density, high strength and large audio impedance; the aperture is small, the intensity is high, and the resonance frequency is high; the thickness is large and the resonance frequency is low. Preferably, the fire-retardant kraft paper honeycomb is adopted, the cost is low, the production process is mature, the surface of the honeycomb is treated by phenolic resin, epoxy resin or vinyl resin for shaping, the water resistance is good,high strength and the density of the honeycomb is 10-50g/m 2 The aperture is 10-50 mm (side length is 5.5-30), and the thickness is 5-100 mm. Besides hexagonal honeycomb, square or rectangular honeycomb with low cost can be selected, and the honeycomb is formed by mutually embedding high-rigidity paperboards.
In a specific embodiment, the microporous plate material is glass fiber reinforced composite material, plastic or metal, the thickness is 0.1-2 mm, the aperture is 0.02-2 mm, the aperture ratio is 1% -10%, the glass fiber reinforced vinyl resin composite material is preferably selected as a substrate of the microporous plate, and in the production process, when the resin is not completely solidified (when the resin loses fluidity and the strength is very low), the through hole is extruded by adopting a template with an iron needle. Damping glue is adopted when the honeycomb is glued, the damping factor of the damping glue is better than 0.2, and the bonding strength is better than 5MPa.
In one embodiment, the composite foam material of filling expanded graphite worms and resin in the honeycomb sandwich structure has a density of 0.005 to 0.5g/cm 3 . The graphite worms are prepared by expanding expandable graphite at high temperature in a high-temperature furnace, the expandable graphite is continuously introduced into the furnace by adopting screw feeding, the volume expansion multiple after heating is 100-800 times, the heating temperature is 600-1300 ℃, natural gas combustion airflow heating, electric heating, microwave heating and the like can be adopted, so long as the required expansion multiple can be obtained by rapidly heating the expandable graphite, the worms are led out and recycled along with the airflow, the expandable graphite is preferably expanded by adopting an electric heating converter, and the inclination angle of the converter is 30-70 degrees. The expandable graphite is obtained by acid oxidation intercalation, and is mainly prepared by a sulfuric acid intercalation process, and the particle size of the graphite also influences expansion times, and the larger the particle size is, the higher the expansion times are. The resin is epoxy, polyurethane, synthetic rubber solution, synthetic latex emulsion, natural latex emulsion, etc., and can be atomized and mixed with graphite worms. The non-atomized resin is directly mixed with graphite worms to cause uneven mixing, worm structure damage and the like. The weight ratio of the expanded graphite to the resin is 100:10 to 500, preferably 100:20 to 100.
In a specific embodiment, the substrate material is made of metal with high acoustic resistance, and is glued with the honeycomb layer by using damping glue, preferably a steel plate with the thickness of 1-3 mm, so that the substrate material has low cost and can reflect more than 99% of sound wave energy in air.
In a second aspect, an embodiment of the present utility model provides a method for manufacturing a multi-layer broadband noise reduction structure including low frequencies, including the following steps:
s1, determining structural characteristics of a multilayer honeycomb sandwich structure, characteristics of a filling expanded graphite composite material and sizes and numbers of micro holes by using finite element simulation software;
s2, stretching the honeycomb blocks by using a stretcher, fixing the honeycomb blocks on a tooling bracket, immersing the honeycomb blocks in a resin solution tank for 2-5 minutes, taking out the honeycomb blocks, drying the honeycomb blocks by using warm air, and curing the honeycomb blocks in a baking oven at 120 ℃.
S3, expanding expandable graphite in a high-temperature furnace according to the characteristics of the filled expanded graphite composite foam material to obtain graphite worms;
s4, mixing the graphite worms with resin according to the characteristics of the filled expanded graphite composite foam material, and spraying the resin into the worms in stirring by adopting a resin atomization process;
s5, filling the honeycomb into a honeycomb fixed in a die according to the design amount, and carrying out hot press shaping by a hot press;
s6, punching the micro-porous plate according to the design, wherein the punching method can adopt laser, punching, hot-pressing punching and the like, or adopts materials with holes, such as punching in the preparation process of the glass fiber composite plate; coating damping adhesive, blowing the damping adhesive blocking the micropores by adopting high-pressure air flow, or punching holes by using laser after coating the damping adhesive;
s7, combining each layer of honeycomb with the micro-pore plate coated with the damping adhesive, the skin and the substrate as required, and adopting a hot press to perform hot-press bonding to form a whole, wherein the hot-press temperature and the hot-press pressure are determined according to the technological conditions of the damping adhesive.
The mixing method of the graphite worms and the resin can adopt a spiral stirring kettle or a roller mixer, the resin solution is atomized and sprayed into the worms while stirring the worms, and air atomization or ultrasonic atomization can be adopted, so that the atomized particle size is uniform, and the process equipment is mature. If emulsion or solution with solvent is adopted, the water and the solvent are required to be dried, the spiral ribbon stirring kettle is required to be provided with a heater, the temperature is 50-70 ℃, and the solvent is stirred until the solvent is completely volatilized.
The weight ratio of each component in the latex is natural latex: sulfur: zinc oxide: anti-aging agent: deionized water = 100:0.5 to 2:0.5 to 3:0.2 to 1: 5-20, mixing other components except the natural latex with deionized water, ball-milling to obtain grinding slurry of the vulcanized package, and mixing with the natural latex.
Hot-press forming of worm and resin adopts a hot press, the temperature and the pressure of the hot press are respectively 50-200 ℃ and 0.3-2 MPa, the hot-press temperature is determined by the curing and vulcanization temperatures of resin and latex, the curing temperature of vinyl resin and epoxy resin is below 80 ℃, and the vulcanization temperature of rubber exceeds 120 ℃; the pressure of the press is related to the density of the syntactic foam, the higher the density the greater the pressure; the hot pressing time is 10-30 minutes, which is the same as the curing time and the vulcanizing time, and the higher the temperature is, the shorter the vulcanizing time is.
Kraft honeycomb made by the eight-way machine and the like requires to increase its strength and water and moisture resistance by coating resin, and an economical method is to impregnate a resin solution, for example, a 5-30% aqueous phenolic resin solution, stretch the honeycomb block by a stretcher, fix the honeycomb block on a tooling support, impregnate the honeycomb block in a resin solution tank for 2-5 minutes, take out the honeycomb block, dry the honeycomb block by warm air, and then cure the honeycomb block in an oven at 120 ℃. The higher the concentration of resin, the greater the strength of the honeycomb.
The thickness of the damping adhesive coated on the surface of the micropore plate influences the shock absorption and noise reduction and the adhesive bonding strength, the reasonable thickness is 0.1-0.3 mm, the thickness is required to be coated according to the design requirement, the tolerance is not more than +/-15%, and the coating method can adopt a screen printing method, a doctor blade method, a roller transfer method and the like.
The temperature and pressure during hot-pressing bonding assembly are lower than the minimum setting temperature and pressure of the graphite worm resin foam, generally 50-70 ℃, 0.1-0.2 MPa and the hot-pressing time is 2-5 minutes.
Drawings
FIG. 1 is a cross-sectional view of a broadband noise reduction structure from low frequency to high frequency of the present utility model having a total thickness of 50mm or 75 mm;
FIG. 2 is a cross-sectional view of a broadband noise reduction structure from low frequency to high frequency of 100mm in thickness according to the present utility model;
the reference numerals are: 1. a microplate; 2. a honeycomb sandwich structure; 3. a composite foam material; 4. a substrate iron plate; 5. micropores.
Detailed Description
The technical scheme of the utility model is further specifically described by the following specific examples. It should be understood that the practice of the utility model is not limited to the following examples, but is intended to be within the scope of the utility model in any form and/or modification thereof. In the present utility model, unless otherwise specified, all parts and percentages are by weight, and the equipment, materials, etc. used are commercially available or are conventional in the art. The methods in the following examples are conventional in the art unless otherwise specified.
The utility model provides a broadband noise reduction structure of composite expanded graphite from low frequency to high frequency, which is a multi-layer honeycomb sandwich structure with a skin, wherein the sides between every two layers of honeycombs and facing noise are bonded by damping glue through a micro-pore plate, a composite foam material of expanded graphite and resin is filled in the honeycomb sandwich structure, and the side not facing noise is a substrate and does not need micro-pores.
Optionally, the audio impedance and loss of each layer of the multilayer honeycomb sandwich structure can be regulated and controlled by the size of the honeycomb, the filling density of the composite material of the expanded graphite and the resin, and the material selection, thickness, aperture and number of the micropore plates, and the acoustic impedance of the honeycomb sandwich structure is in the range of 3x10 3 ～2x10 6 kg/m 2 S, the impedance of the honeycomb layer close to the noise side is the lowest, the impedance of each layer increases along with the increase of the distance from the sound source, so that the honeycomb layer is combined to form a broadband noise reduction structure, the noise reduction frequency is from 10Hz to 20kHz, and the design can be optimized by adopting finite element simulation software.
Optionally, the honeycomb wall material is at least one of aluminum foil, stainless steel foil, kraft paper, aramid paper, glass fiber composite material, glass fiber paper, plastic and the like, and the density of the honeycomb is 10-200g/m 2 The aperture is 3-50 mm (side length is 1.8-30 mm), and the thickness is 2-100 mm. Preferably, kraft paper honeycomb is adopted, the aperture is 10-50 mm (side length is 5.5-30 mm), and the thickness isThe degree is 5-100 mm. The honeycomb section can be hexagonal, rectangular formed by stretching the hexagonal, square and rectangular formed by embedding flat plates.
Optionally, the microporous plate material is glass fiber reinforced composite material, plastic or metal, the thickness is 0.1-2 mm, the aperture is 0.02-2 mm, and the aperture ratio is 1% -10%. Damping glue is adopted when the honeycomb is glued, the damping factor of the damping glue is better than 0.2, the bonding strength is better than 5MPa, and a glass fiber reinforced vinyl resin composite material is preferably selected as a substrate of a micropore plate.
Alternatively, the honeycomb sandwich structure can be filled with a composite foam material of porous expanded graphite and resin, and the density of the composite foam material is 0.005-0.5 g/cm 3 . The expanded graphite (graphite worm) is prepared by high-temperature expansion of expandable graphite, the volume expansion multiple of the expanded graphite after heating is 100-800 times, and the specific surface area is better than 20m 2 And/g. The resin is epoxy, polyurethane, synthetic rubber solution, synthetic latex emulsion, natural latex emulsion, etc., and can be atomized and mixed with graphite worms. The weight ratio of graphite worms to resin is 100:10 to 500, preferably 100:20 to 100.
Alternatively, the substrate material is made of metal with high acoustic resistance, and is glued to the honeycomb layer by using damping glue, preferably a steel plate.
Optionally, the kraft honeycomb is impregnated with a resin solution, wherein the impregnating resin is phenolic resin, epoxy resin, vinyl resin, or the like, and the concentration of the resin is 5-30%.
The utility model also provides a manufacturing method of the low-frequency to high-frequency broadband noise reduction structure, which comprises the following steps:
s1, determining structural characteristics of a multilayer honeycomb sandwich structure, characteristics of a filling expanded graphite composite material and sizes and numbers of micro holes by using finite element simulation software;
s2, stretching the honeycomb blocks by using a stretcher, fixing the honeycomb blocks on a tooling bracket, immersing the honeycomb blocks in a resin solution tank for 2-5 minutes, taking out the honeycomb blocks, drying the honeycomb blocks by using warm air, and curing the honeycomb blocks in a baking oven at 120 ℃.
S3, expanding expandable graphite in a high-temperature furnace according to the characteristics of the filled expanded graphite composite foam material to obtain graphite worms;
s4, mixing the graphite worms with resin according to the characteristics of the filled expanded graphite composite foam material, and spraying the resin into the worms in stirring by adopting a resin atomization process;
s5, filling the mixture of the graphite worm resin into a honeycomb fixed in a die according to the design amount, and carrying out hot press shaping by a hot press;
s6, punching the micro-pore plate according to the design, wherein the punching method can adopt laser, punching, hot-pressing punching and the like, or adopts the materials with holes, coats damping glue, adopts high-pressure air flow to blow the damping glue blocking the micro-pores, or uses laser to punch holes after coating the damping glue;
s7, combining each layer of honeycomb with the micro-pore plate coated with the damping adhesive, the skin and the substrate as required, and performing hot-pressing bonding by a hot press to form a whole.
Optionally, a continuous process apparatus is used to produce graphite worms, the core of which is a high temperature furnace, the expandable graphite is introduced from the upper part of the furnace and the bottom is collected, or the expandable graphite is introduced into the high temperature gas flow of the furnace, and the graphite worms are collected after being cooled along with the gas flow. Preferably, the expandable graphite is expanded by an electrothermal converter, and the inclination angle of the converter is 30-70 degrees.
Optionally, the mixing process of the graphite worms and the resin adopts a heated spiral ribbon stirring kettle, the heating temperature is 30-80 ℃, and the solvent in the resin is dried.
The utility model is further described below with reference to examples.
Example 1
The utility model provides a broadband noise reduction structure from low frequency to high frequency, the total thickness is 75mm, the design is shown in table 1, and the sectional view is shown in fig. 1. The performance of the sound insulation board is that the sound absorption coefficient from 125Hz to 500Hz is better than 0.5, the sound absorption coefficient above 500Hz is better than 0.75, and the sound insulation effect is better than 40dB.
Table 1: and (3) designing a multi-layer broadband noise reduction structure.
Kraft honeycomb produced by an eight-direction machine is preferably selected, and the gram weight of the paper is 110g/m 2 The node glue is water glass. The honeycomb block was stretched to the desired length and fixed to a metal support, impregnated with a 10% phenolic resin solution for 2 minutes, air dried at 50 c, oven cured at 120 c for 30 minutes to set, and cut to the desired thickness of 10mm, 43mm and 20mm with high speed band saw blades. The compression strength of the honeycomb with the side length of 6mm is more than 0.2MPa.
Preferably, expandable graphite with expansion ratio of #80 of 300 is selected, the expandable graphite is expanded by an electrothermal converter with the temperature of 1100 ℃ of the furnace, and the inclination angle of the converter is 30-70 degrees, so that graphite worms with expansion ratio of 320 times are obtained. And (3) stirring worms in a spiral stirring kettle, atomizing and spraying the double-component polyurethane accounting for 30% of the weight of the worms, and stirring for 5-10 minutes until the mixture is uniform.
The honeycomb is placed in a cavity of a metal mold by the preferred process, worms which are required to be mixed with resin are paved on the honeycomb, the honeycomb is assembled, and the honeycomb filled with the expanded graphite worm composite material is obtained by hot pressing for 3-5 minutes at 80 ℃.
The outer skin is vinyl resin glass fiber composite material, the middle micropore plate adopts highland barley paper base material, a roller sizing machine is adopted, damping glue with the thickness of 0.1mm is evenly coated, and laser drilling is adopted according to the requirements of Table 1 after the solvent is dried. The substrate is an iron plate with the thickness of 1mm, and a roller gluing machine is adopted to evenly coat damping glue with the thickness of 0.1 mm.
The skin, the filled honeycomb and microplates and the substrate were sequentially stacked and hot pressed on a hot press at 60 ℃ for 5 minutes at a pressure of 0.1MPa.
And (5) spraying anti-corrosion paint and finishing paint on the surface of the substrate iron plate.
The compressive strength of the multi-layer noise reduction structure was measured to be about 0.4MPa.
Example 2
The utility model provides a broadband noise reduction structure from low frequency to high frequency, the total thickness is 50mm, the design is shown in table 2, and the sectional view is shown in fig. 1. The performance of the sound insulation board is that the sound absorption coefficient from 125Hz to 500Hz is better than 0.3, the sound absorption coefficient above 500Hz is better than 0.65, and the sound insulation effect is better than 35dB.
Table 2: and (3) designing a multi-layer broadband noise reduction structure.
Kraft honeycomb produced by an eight-direction machine is preferably selected, and the gram weight of the paper is 110g/m 2 The node glue is water glass. The honeycomb block was stretched to the desired length and fixed to a metal support, impregnated with a 10% phenolic resin solution for 2 minutes, air dried at 50 c, oven cured at 120 c for 30 minutes to set, and cut to the desired thickness of 6mm, 32mm and 10mm with high speed band saw blades. The compression strength of the honeycomb with the side length of 6mm is more than 0.2MPa.
Preferably, expandable graphite with expansion ratio of #50 of 500 is selected, the expandable graphite is expanded by an electrothermal converter with the temperature of 1100 ℃ at an inclined angle of 30-70 DEG, and graphite worms with expansion ratio of 530 times are obtained. Heating the mixture to 60 ℃ in a spiral stirring kettle, stirring worms, atomizing and spraying natural emulsion with the weight of the worms calculated according to the solid content of 40%, and stirring for 20-30 minutes until the water is evaporated. The weight ratio of the components of the latex is natural latex: sulfur: zinc oxide: anti-aging agent: deionized water = 100:0.5 to 2:0.5 to 3:0.2 to 1: 5-20, mixing other components except the natural latex with deionized water, ball-milling to obtain grinding slurry of the vulcanized package, and mixing with the natural latex.
The honeycomb is placed in a cavity of a metal mold, worms which are required to be mixed with resin are paved on the honeycomb, the honeycomb is assembled, and the honeycomb filled with the expanded graphite worm composite material is obtained by hot pressing for 3-5 minutes at 150 ℃.
The outer skin is vinyl resin glass fiber composite material, the middle micropore plate adopts highland barley paper base material, a roller sizing machine is adopted, damping glue with the thickness of 0.1mm is evenly coated, and laser drilling is adopted according to the requirements of Table 2 after the solvent is dried. The substrate is an iron plate with the thickness of 1mm, and a roller gluing machine is adopted to evenly coat damping glue with the thickness of 0.1 mm.
The skin, the filled honeycomb and microplates and the substrate were sequentially stacked and hot pressed on a hot press at 60 ℃ for 5 minutes at a pressure of 0.1MPa.
And (5) spraying anti-corrosion paint and finishing paint on the surface of the substrate iron plate.
The compressive strength of the multi-layer noise reduction structure was measured to be about 0.4MPa.
Example 3
The utility model provides a broadband noise reduction structure from low frequency to high frequency, the total thickness is 100mm, the design is shown in table 3, and the sectional view is shown in fig. 2. The performance of the sound insulation board is that the sound absorption coefficient from 125Hz to 500Hz is better than 0.6, the sound absorption coefficient above 500Hz is better than 0.8, and the sound insulation effect is better than 40dB.
Table 3: and (3) designing a multi-layer broadband noise reduction structure.
Highland barley paper with the thickness of 0.5mm is preferably used as a raw material of the mutually embedded square honeycomb, cut into paper sheets with the width of 98.6mm, are separated by 50mm, cut into mutually embedded gaps with the depth of 50mm, and then mutually embedded into the honeycomb.
Preferably, expandable graphite with expansion ratio of #50 of 500 is selected, the expandable graphite is expanded by an electrothermal converter with the temperature of 1100 ℃ at an inclined angle of 30-70 DEG, and graphite worms with expansion ratio of 530 times are obtained. And (3) stirring worms in a spiral stirring kettle, atomizing and spraying the double-component polyurethane accounting for 30% of the weight of the worms, and stirring for 5-10 minutes until the mixture is uniform.
The honeycomb is placed in a cavity of a metal mold, a corresponding upper mold is provided with gaps corresponding to honeycomb walls, the mold can enter the honeycomb, worms which are required to be mixed with resin in a layer 3 are paved on the honeycomb, the mold is clamped to the thickness of the layer 3, worms which are required to be mixed with resin in a layer 2 are paved on the honeycomb, the mold is clamped to the thickness of the layer 2 plus the layer 3, worms which are required to be mixed with resin in the layer 1 are paved on the honeycomb, the mold is clamped to the thickness of the honeycomb, and the honeycomb filled with the expanded graphite worm composite material is obtained through hot pressing at 80 ℃ for 7-10 minutes.
The outer skin is made of microporous vinyl resin glass fiber composite material, the substrate is an iron plate with the thickness of 1mm, a roller sizing machine is adopted, damping glue with the thickness of 0.1mm is uniformly coated, and laser drilling is adopted according to the requirements of Table 3 after the solvent is dried. The substrate is an iron plate with the thickness of 1mm, and a roller gluing machine is adopted to evenly coat damping glue with the thickness of 0.1 mm.
The skin, the filled honeycomb and the substrate are sequentially stacked, and hot pressed on a hot press at 60 ℃ for 3 minutes at a pressure of 0.1MPa.
And (5) spraying anti-corrosion paint and finishing paint on the surface of the substrate iron plate.
The compressive strength of the multi-layer noise reduction structure was measured to be about 0.15MPa.
Reference example 1
As a reference example of the present utility model, the total thickness was 75mm, and the design thereof was as shown in Table 4. The performance of the sound insulation board is that the sound absorption coefficient from 125Hz to 500Hz is better than 0.3, the sound absorption coefficient above 500Hz is better than 0.6, and the sound insulation effect is better than 30dB.
Table 4: and (3) designing a multi-layer broadband noise reduction structure.
The multilayer honeycomb sandwich structure was processed according to the production process of example 1 and the compressive strength of the multilayer noise reduction structure was measured to be about 0.3MPa.
Reference example 2
As a reference example of the present utility model, the total thickness was 75mm, and the design thereof was as shown in Table 1. The performance of the sound insulation board is that the sound absorption coefficient from 125Hz to 500Hz is better than 0.4, the sound absorption coefficient above 500Hz is better than 0.75, and the sound insulation effect is better than 30dB.
The honeycomb sandwich structure was bonded by using an epoxy resin adhesive instead of the damping adhesive, and the multilayer honeycomb sandwich structure was processed according to the production process of example 1, and the compressive strength of the multilayer noise reduction structure was measured to be about 0.4MPa.
Comparison of the performance of the examples with the reference example is shown in table 5, which shows that the use of the expanded graphite worm resin composite filler and damping gel is beneficial for improving the sound absorption coefficient.
Table 5: comparison of examples with reference examples performance
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing description is only of the preferred embodiments of the present utility model and is not intended to limit the scope of the present utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model are included in the protection scope of the present utility model.
Claims (7)
1. The broadband noise reduction structure of the composite expanded graphite from low frequency to high frequency is characterized in that the noise reduction structure is a multi-layer honeycomb sandwich structure with a skin, a micro-pore plate is adopted between each layer of honeycomb of the multi-layer honeycomb sandwich structure with the skin and on the side facing noise and is bonded through damping glue, the multi-layer honeycomb sandwich structure with the skin is filled with a composite foam material of expanded graphite and resin, and a substrate without micropores is arranged on the side, facing noise, of the multi-layer honeycomb sandwich structure with the skin.
2. The broadband noise reduction structure from low frequency to high frequency according to claim 1, wherein the audio impedance and loss of each layer of the skin-covered multi-layer honeycomb sandwich structure are regulated and controlled by the size of the honeycomb, the filling density of the composite material of the expanded graphite and the resin, and the material selection, the thickness, the pore diameter and the number of the micropore plates;
the sound impedance range of the multilayer honeycomb sandwich structure with the skin is 3 multiplied by 10 3 ～2×10 6 kg/m 2 S, the impedance of the honeycomb layer close to the noise side is the lowest, the impedance of each layer increases along with the increase of the distance from the sound source, so that the honeycomb layer is combined to form a broadband noise reduction structure, and the noise reduction frequency is from 10Hz to 20kHz.
3. The broadband noise reduction structure from low frequency to high frequency according to claim 1, wherein the density of the cells of the skinned multilayer honeycomb sandwich structure is 10-200g/m 2 The aperture is 3-50 mm or the side length is 1.8-30 mm, and the thickness is 2-100 mm.
4. The broadband noise reduction structure from low frequency to high frequency according to claim 3, wherein the multi-layer honeycomb sandwich structure with skin adopts kraft paper honeycomb, the aperture is 10-50 mm or the side length is 5.5-30 mm, the thickness is 5-100 mm, and the honeycomb section comprises at least one of hexagon, rectangle formed by over-stretching hexagon, square formed by mutually embedding flat plates and rectangle formed by mutually embedding flat plates;
the kraft honeycomb is subjected to resin solution impregnation treatment.
5. The broadband noise reduction structure from low frequency to high frequency according to claim 1, wherein the material of the micro-porous plate is glass fiber reinforced composite material, plastic or metal, the thickness is 0.1-2 mm, the aperture is 0.02-2 mm, and the aperture ratio is 1% -10%;
damping glue is adopted when the micro-pore plate is glued with the honeycomb, the bonding strength is higher than 5MPa, and glass fiber reinforced vinyl resin composite material is selected as a base material of the micro-pore plate.
6. The broadband noise reduction structure from low frequency to high frequency according to claim 1, wherein the multi-layered honeycomb sandwich structure with skin is filled with a composite foam material of porous expanded graphite and resin, and the density of the filled material is 0.005-0.5 g/cm 3 ；
The expanded graphite is prepared by high-temperature expansion of expandable graphite, the volume expansion multiple of the heated expandable graphite is 100-800 times,specific surface area is better than 20m 2 /g。
7. The broadband noise reduction structure from low frequency to high frequency according to claim 1, wherein the substrate is made of metal with high acoustic resistance, and is glued with the honeycomb layer by using damping glue.
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