CN108395637B - Sound-absorbing microsphere material and preparation method thereof - Google Patents
Sound-absorbing microsphere material and preparation method thereof Download PDFInfo
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- CN108395637B CN108395637B CN201810131978.XA CN201810131978A CN108395637B CN 108395637 B CN108395637 B CN 108395637B CN 201810131978 A CN201810131978 A CN 201810131978A CN 108395637 B CN108395637 B CN 108395637B
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Abstract
The invention relates to the technical field of loudspeakers, in particular to a sound-absorbing microsphere material and a preparation method thereof. The preparation method comprises the following steps: stirring zeolite particles, elastomer powder, an adhesive and solvent water to obtain a mixed suspension solution, wherein the adding mass of the elastomer powder is 2-4% of the total mass of the mixed suspension solution; and granulating and screening the mixed suspension solution to obtain the sound absorption microsphere material with the target particle size. According to the invention, on the basis of the bonding preparation of the porous zeolite sound absorption microsphere material for the traditional loudspeaker, the elastomer powder with specific content is introduced, the problem of low impact toughness of the sound absorption microsphere material generally existing can be solved without increasing the content of an adhesive, and the zeolite sound absorption microsphere material with excellent ageing resistance and longer service life can be conveniently and massively prepared.
Description
[ technical field ] A method for producing a semiconductor device
The invention relates to the technical field of loudspeakers, in particular to a sound-absorbing microsphere material and a preparation method thereof.
[ background of the invention ]
The prior sound-absorbing microsphere material for the loudspeaker is mainly obtained by bonding and molding a plurality of zeolite particles. After the sound-absorbing microsphere material is prepared in this way, the sound-absorbing microsphere material can be filled into a speaker cavity. When the loudspeaker works, the cavity can generate strong vibration, and the condition that zeolite particles on the outer layer fall off and even the whole sphere is broken can occur in the conventional sound-absorbing microsphere material, so that the sound-absorbing effect and the service life of the loudspeaker are influenced. The existing solutions are generally: the impact resistance problem of the prepared sound-absorbing microsphere material at the conventional working temperature and frequency is effectively solved by increasing the content of the adhesive or selecting the adhesive with low glass transition temperature.
The inventor discovers that in the process of implementing the invention: in order to increase the impact resistance of the sound-absorbing microsphere material, the mode of increasing the content of the adhesive or the adhesive with a low glass transition temperature is selected, which can cause the problems of hole blockage of the adhesive, poor high-temperature weather resistance of the sound-absorbing microsphere material, reduction of the pore volume and the specific surface area of the material, and the like, and the problem can also greatly reduce the overall sound absorption effect of the microsphere material.
[ summary of the invention ]
An object of an embodiment of the present invention is to provide a sound-absorbing microsphere material and a preparation method thereof, which aim to solve the problem that the existing sound-absorbing microsphere material is difficult to have high impact resistance on the basis of maintaining high sound absorption performance.
In order to solve the above technical problem, an embodiment of the present invention provides the following technical solutions:
in a first aspect, embodiments of the present invention provide a method for preparing a sound-absorbing microsphere material,
the method comprises the following steps: stirring zeolite particles, elastomer powder, an adhesive and solvent water to obtain a mixed suspension solution, wherein the adding mass of the elastomer powder is 2-4% of the total mass of the mixed suspension solution; and granulating and screening the mixed suspension solution to obtain the sound absorption microsphere material with the target particle size.
Optionally, the granulating and screening the mixed suspension solution to obtain the sound absorption microsphere material with a target particle size specifically includes: carrying out spray drying granulation on the mixed suspension solution to obtain primary formed particles; drying the preliminarily molded particles for 1-3 h at 100-150 ℃ to obtain dried particles; and screening the dry particles by using a screen to obtain the sound absorption microsphere material with the target particle size.
Optionally, the target particle size is 150 to 380 μm.
Optionally, the added mass of the elastomer powder is 2.5-3.5% of the total mass of the mixed suspension solution.
Optionally, the particle diameter of the zeolite particle raw material is in a range of 0.5-5 μm.
Optionally, the particle diameter of the zeolite particle raw material is in a range of 1-3 μm.
Optionally, the elastomer powder is made of one or more of the following cross-linked rubbers: crosslinked natural rubber, crosslinked butadiene rubber, crosslinked carboxylated styrene-butadiene rubber, crosslinked polybutadiene rubber, crosslinked nitrile rubber, crosslinked carboxylated nitrile rubber, crosslinked chloroprene rubber, crosslinked acrylate rubber, crosslinked silicone rubber and crosslinked butadiene-pyridine rubber.
Optionally, the elastomer powder has a particle diameter of 20nm to 2 μm.
Optionally, the elastomer powder has a particle diameter of 50nm to 500 nm.
In a second aspect, the embodiment of the present invention provides a sound-absorbing microsphere material prepared by using the above preparation method of a sound-absorbing microsphere material.
According to the invention, on the basis of the bonding preparation of the porous zeolite sound absorption microsphere material for the traditional loudspeaker, the elastomer powder with specific content is introduced, the problem of low impact toughness of the sound absorption microsphere material generally existing can be solved without increasing the content of an adhesive, and the zeolite sound absorption microsphere material with excellent ageing resistance and longer service life can be conveniently and massively prepared.
[ description of the drawings ]
Fig. 1 is a schematic flow chart of a method for preparing a sound-absorbing microsphere material according to an embodiment of the present invention.
[ detailed description ] embodiments
In order to make the objects, aspects and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The embodiments of the present invention are mainly applied to the sound-absorbing material in the speaker, and in order to facilitate understanding of the embodiments of the present invention by those skilled in the art, the mechanism of action of the sound-absorbing material applied to the speaker by the inventors is described as follows:
a speaker is an energy converter for converting an electric signal into an acoustic signal, and is widely used in various electronic devices. The inner cavity of the shell of the loudspeaker module can be structurally divided into a front sound cavity and a rear sound cavity, wherein the most important factor influencing the tone quality of the loudspeaker is the sound absorption effect of the rear cavity. The new generation of micro-speakers mostly adopt porous sound-absorbing materials to realize sound absorption, while the zeolite sound-absorbing microspheres are one of granular porous sound-absorbing materials, the surfaces of the microspheres are rich in pores, and the pores are mutually communicated and go deep into the microspheres. The sound wave is a mechanical energy, and after entering the porous sound absorption material, air vibration is caused, and the vibration is blocked by the bent pore walls, so that the air is rubbed with the pore walls to cause energy loss. Meanwhile, the sound waves can undergo multiple reflection and refraction between the pore walls, so that most of energy is changed into heat energy to be dissipated to the environment, and the noise reduction effect is achieved. In addition, the porous sound-absorbing material has a larger surface area and quick gas adsorption-desorption properties, so that the resonance space of the sound cavity can be virtually increased, and the medium-low frequency resonance frequency F0 of the loudspeaker module can be effectively reduced.
As described in the background art, when the speaker operates, the cavity may vibrate strongly, and the conventional sound-absorbing material may have outer zeolite particles falling off or even the whole ball breaking, which affects the sound-absorbing effect and the service life of the speaker.
Based on the above, the embodiment of the invention provides a sound-absorbing microsphere material which is convenient to prepare in a large scale, and the problem of low impact of the existing sound-absorbing material is solved by adding elastomer powder as a structural mechanical buffer filler in the preparation process of the sound-absorbing microsphere material. The sound-absorbing microsphere material provided by the embodiment of the invention has good acoustic performance and application advantages.
First, a method for preparing the sound-absorbing microsphere material according to the embodiments of the present invention will be described.
Referring to fig. 1, fig. 1 is a schematic flow chart of a method for preparing a sound-absorbing microsphere material according to an embodiment of the present invention, as shown in fig. 1, the method 100 includes:
and step 10, stirring the zeolite particles, the elastomer powder, the adhesive and the solvent water to obtain a suspension solution.
The zeolite particles can be selected from zeolite particles with one or more structures of FER zeolite, MFI zeolite, ME L zeolite, CHA zeolite, IHW zeolite, IWV zeolite, ITE zeolite, UT L zeolite, VET zeolite, MTW zeolite and FAU zeolite, and preferably, the silicon-aluminum ratio of the raw material of the zeolite particles is more than 200, and the higher silicon-aluminum ratio can increase the hydrophobicity of the zeolite particles, reduce the hygroscopicity of the sound absorption microsphere material and further increase the aging resistance of the sound absorption microsphere material.
The zeolite particle feedstock has intrinsic pores ranging in diameter from 0.38nm to 0.74nm, depending on the type of zeolite selected for the application. Preferably, the zeolite particles have a diameter of 0.4nm to 0.6 nm. In this example, the diameter of the zeolite particles is preferably 0.4nm to 0.6nm, while ensuring the small pore diameter of the raw material while maintaining the gas compliance. The particle diameter of the zeolite particle raw material is 0.5-5 μm, preferably 1-3 μm.
In this embodiment, the added mass of the zeolite particles is 20% to 40%, preferably 25% to 35%, of the total mass of the mixed suspension solution; wherein, the total mass of the suspension solution is calculated by the sum of the total mass of the zeolite particles, the elastomer powder, the adhesive and the solvent water.
Wherein, the elastomer powder can be prepared by powdering one or more of the following cross-linked rubbers:
crosslinked natural rubber, crosslinked butadiene rubber, crosslinked carboxylated styrene-butadiene rubber, crosslinked polybutadiene rubber, crosslinked nitrile rubber, crosslinked carboxylated nitrile rubber, crosslinked chloroprene rubber, crosslinked acrylate rubber, crosslinked silicone rubber, crosslinked butadiene-styrene rubber, and the like;
the pulverization mode of the crosslinked rubber to obtain the elastomer powder can be various modes as follows: mechanical pulverization, spray drying, flash drying, freeze pulverization, co-agglomeration, and the like. Preferably, in consideration of the elastomer powder particle size used in the present invention, a preferred method is a spray drying method. In this embodiment, the elastomer powder particles are prepared with a diameter of 20nm to 2 μm, preferably 50nm to 500 nm. This is because: the small rubber powder can block the surface pore channels of zeolite raw material particles, reduce the integral specific surface area and air smoothness of the microsphere material and is unfavorable for sound absorption performance. 2. The larger the rubber powder particles are, the more difficult it is to fill the gaps between the zeolite particles, and the smaller the increase in bulk density of the microsphere material is, and in this embodiment, the elastomer powder of 50nm to 500nm is preferable in view of the above.
In some embodiments, the elastomer powder may also be made from a cross-linked rubber and plastic blending system, i.e., from a vulcanized thermoplastic elastomer.
The cross-linked rubber, as mentioned above, the plastic may be one or more of: polyamide, polypropylene, polyethylene, polyvinyl chloride, polyurethane, epoxy, polyester, polycarbonate, polyoxymethylene, polystyrene, polyphenylene oxide, polyphenylene sulfide, polyimide, or polysulfone. The preparation method of the elastomer powder is a preparation method commonly used in the field, and a person skilled in the art can prepare the elastomer powder according to the existing preparation method of the elastomer powder, and details are not repeated herein.
In the present embodiment, the mass of the elastomer powder accounts for 2% to 4%, preferably 2.5% to 3.5%, of the total mass of the suspension solution; the total mass of the suspension solution is calculated by the sum of the total mass of the zeolite particles, the elastomer powder and the adhesive emulsion.
Wherein, the adhesive can be inorganic adhesive and/or polymer adhesive; the inorganic adhesive comprises: one or more of silica sol, aluminum sol and kaolin; the polymer adhesive comprises: one or more of polyacrylates, polyurethanes and epoxy resins.
And the adhesive, the zeolite particles and the elastomer powder are fully mixed by stirring through solvent water at normal temperature to obtain a mixed suspension solution.
In the embodiment, the mechanical stirring speed is 250-1000 rpm, and the stirring time is 1-4 h. One skilled in the art can also make appropriate adjustments of the stirring speed and the stirring time according to the actual stirring situation, wherein the slower the stirring speed, the longer the stirring time, and correspondingly, the faster the stirring speed, the shorter the stirring time.
In the embodiment, the mass of the adhesive accounts for 1-10%, preferably 2-5% of the total mass of the suspension solution; wherein, the total mass of the suspension solution is calculated by the sum of the total mass of the zeolite particles, the elastomer powder, the adhesive and the solvent water.
Preferably, while stirring and mixing, the solvent water may be added so that the total mass of the zeolite particles, the elastomer powder and the binder added in the resulting mixed suspension solution is the following of the total mass of the suspension: 25 to 50%, preferably 30 to 40%.
And 20, granulating and screening the suspension solution to obtain the sound absorption microsphere material with the target size.
In this embodiment, the following method can be selected for granulation: spray drying granulation, extrusion granulation, melt granulation, rotary granulation or fluidized bed granulation. Preferably, after granulation by spray drying, the sound absorption microsphere material with the target size can be obtained by screening.
The process of granulation using spray drying is described in detail below, and includes:
1. carrying out spray drying granulation on the mixed suspension solution in a nitrogen atmosphere or an air atmosphere to obtain primary formed particles;
2. drying the preliminarily molded particles for 1-3 h at 100-150 ℃ to obtain dried particles;
3. and screening the dry particles by using a 40-100 mesh screen to obtain the sound absorption microsphere material with the target particle size.
Among them, it is easy for those skilled in the art to understand that the lower the drying temperature, the longer the drying time, and correspondingly, the higher the drying temperature, the shorter the drying time.
In some embodiments, non-crosslinked rubber powder or adhesive can be selected to adopt rubber emulsion to prepare porous zeolite sound-absorbing microsphere materials with similar particle sizes, and then the similar materials are obtained through a vulcanization process.
According to the preparation method of the sound-absorbing microsphere material provided by the embodiment of the invention, elastomer powder is introduced as a structural mechanical buffer filler in the preparation process. Therefore, the problem of low impact toughness of the sound absorption microsphere material can be solved without increasing the content of an adhesive. Furthermore, in the method, the zeolite particles and the elastomer powder can be processed by using waste molecular sieves and industrial rubber which meet the requirements, so that the method has a certain environment-friendly prospect.
The following describes the preparation method of the sound-absorbing microsphere material and the impact resistance of the sound-absorbing microsphere material in detail with reference to specific examples.
1. Preparation of Sound-absorbing microsphere materials (examples 1-5)
Example 1
1) Dried zeolite raw material particles (zeolite structure is FER, average pore diameter of micropores is about 0.49nm, particle diameter is about 2 μm), fully vulcanized styrene-butadiene rubber powder (particle diameter is about 400nm) and polystyrene-acrylate (adhesive) are added into solvent water, and mechanically stirred for 2h at 500rpm to obtain uniformly dispersed mixed suspension solution (also called slurry).
Wherein the adding mass of the zeolite particles is 25 percent of the total mass of the mixed suspension solution; the adding mass of the fully vulcanized styrene butadiene rubber powder particles is 2.5 percent of the total mass of the mixed suspension solution; the added mass of the polystyrene-acrylate was 2.5% of the total mass of the above mixed suspension solution. In the suspension, the mass of the solid was 30% of the total mass of the mixed suspension.
2) And adding the uniformly dispersed mixed suspension solution into a spray drying granulator, and drying and granulating to obtain primary formed particles, wherein the inlet temperature of the spray drying granulator is 140-160 ℃, the outlet temperature of the spray drying granulator is 100-110 ℃, and the spray pressure of the spray drying granulator is 0.5 MPa.
3) And (3) heating and curing the primarily formed particles in an oven at 120 ℃ for 1.5h, and drying to obtain dried particles.
4) And screening the dried particles by using a screen of 80-100 meshes to obtain the sound absorption microsphere material with the particle size of about 150-180 mu m.
Example 2:
1) dried zeolite raw material particles (zeolite structure is FER, average pore diameter of micropores is about 0.49nm, particle diameter is about 2 μm), fully vulcanized acrylate rubber powder (particle diameter is about 250nm) and polystyrene-acrylate (adhesive) are added into solvent water, and mechanically stirred for 2h at 500rpm to obtain uniformly dispersed mixed suspension solution (also called slurry).
Wherein the adding mass of the zeolite particles is 30 percent of the total mass of the mixed suspension solution; the adding mass of the fully vulcanized acrylate rubber powder particles is 3 percent of the total mass of the mixed suspension solution; the added mass of the polystyrene-acrylate was 3% of the total mass of the mixed suspension solution. In the suspension, the mass of solids was 36% of the total mass of the mixed suspension.
2) And adding the uniformly dispersed mixed suspension solution into a spray drying granulator, and drying and granulating to obtain primary formed particles, wherein the inlet temperature of the spray drying granulator is 140-160 ℃, the outlet temperature of the spray drying granulator is 100-110 ℃, and the spray pressure of the spray drying granulator is 0.4 MPa.
3) And (3) heating and curing the primarily formed particles in an oven at 120 ℃ for 1.5h, and drying to obtain dried particles.
4) And screening the dried particles by using a 60-70-mesh screen to obtain the sound-absorbing microsphere material with the particle size of about 220-250 mu m.
Example 3:
1) adding dried zeolite raw material particles (the zeolite structure is MFI, the average pore diameter of micropores is about 0.55nm, and the particle diameter is about 2 mu m), fully-vulcanized nitrile rubber powder (the particle diameter is about 350nm) and polyurethane (adhesive) into solvent water, and mechanically stirring for 4h at 250rpm to obtain a uniformly-dispersed mixed suspension solution (also called slurry).
Wherein the adding mass of the zeolite particles is 35 percent of the total mass of the mixed suspension solution; the adding mass of the fully vulcanized nitrile rubber powder particles is 2.5 percent of the total mass of the mixed suspension solution; the added mass of the polystyrene-acrylate was 2.5% of the total mass of the above mixed suspension solution. In the suspension, the mass of the solid was 40% of the total mass of the mixed suspension.
2) And adding the uniformly dispersed mixed suspension solution into a spray drying granulator, and drying and granulating to obtain primary formed particles, wherein the inlet temperature of the spray drying granulator is 140-160 ℃, the outlet temperature of the spray drying granulator is 100-110 ℃, and the spray pressure of the spray drying granulator is 0.3 MPa.
3) And (3) heating and curing the primarily formed particles in an oven at 150 ℃ for 1h, and drying to obtain dried particles.
4) And screening the dried particles by using a 40-45-mesh screen to obtain the sound-absorbing microsphere material with the particle size of 325-380 mu m.
Example 4:
1) adding dried zeolite raw material particles (the zeolite structure is MFI, the average pore diameter of micropores is about 0.55nm, and the particle diameter is about 3 mu m), fully-vulcanized carboxylated nitrile rubber powder (the particle diameter is about 300nm) and epoxy resin (adhesive) into solvent water, and mechanically stirring for 4h at 250rpm to obtain a uniformly-dispersed mixed suspension solution (also called slurry).
Wherein the adding mass of the zeolite particles is 30 percent of the total mass of the mixed suspension solution; the adding mass of the fully vulcanized carboxyl nitrile rubber particles is 3 percent of the total mass of the mixed suspension solution; the added mass of the polystyrene-acrylate is 2% of the total mass of the mixed suspension solution. In the suspension, the mass of solids was 35% of the total mass of the mixed suspension.
2) And adding the uniformly dispersed mixed suspension solution into a spray drying granulator, and drying and granulating to obtain primary formed particles, wherein the inlet temperature of the spray drying granulator is 140-160 ℃, the outlet temperature of the spray drying granulator is 100-110 ℃, and the spray pressure of the spray drying granulator is 0.35 MPa.
3) And (3) heating and curing the primarily formed particles in an oven at 150 ℃ for 1h, and drying to obtain dried particles.
4) And screening the dried particles by using a 40-50 mesh screen to obtain the sound absorption microsphere material with the particle size of 270-325 mu m.
Example 5:
1) dried zeolite raw material particles (the zeolite structure is ME L, the average pore diameter of micropores is about 0.55nm, and the particle diameter is about 3 μm) and fully vulcanized butadiene rubber powder (the particle diameter is about 250nm) silica sol (adhesive) are added into solvent water, and mechanically stirred for 2h at 500rpm to obtain uniformly dispersed mixed suspension solution (also called slurry).
Wherein the adding mass of the zeolite particles is 25 percent of the total mass of the mixed suspension solution; the adding mass of the fully vulcanized butadiene rubber particles is 3.5 percent of the total mass of the mixed suspension solution; the added mass of the polystyrene-acrylate was 4.5% of the total mass of the above mixed suspension solution. In the suspension, the mass of solids was 33% of the total mass of the mixed suspension.
2) And adding the uniformly dispersed mixed suspension solution into a spray drying granulator, and drying and granulating to obtain primary formed particles, wherein the inlet temperature of the spray drying granulator is 140-160 ℃, the outlet temperature of the spray drying granulator is 100-110 ℃, and the spray pressure of the spray drying granulator is 0.4 MPa.
3) And (3) heating and curing the primarily formed particles in an oven at 120 ℃ for 2h, and drying to obtain dried particles.
4) And screening the dried particles by using a 60-70-mesh screen to obtain the sound-absorbing microsphere material with the particle size of about 220-250 mu m.
2. Comparative examples
Under the same preparation conditions, examples 1 to 5 were prepared to obtain a sound absorbing microsphere material of comparative example 1 corresponding to example 1, a sound absorbing microsphere material of comparative example 2 corresponding to example 2, a sound absorbing microsphere material of comparative example 3 corresponding to example 3, a sound absorbing microsphere material of comparative example 4 corresponding to example 4, and a sound absorbing microsphere material of comparative example 5 corresponding to example 5, respectively, without adding only rubber powder (elastomer powder) particles.
3. Comparative examples 1-1 and 1-2 of example 1
Changing the ratio of the added mass of the zeolite particle raw material to the total mass of the mixed suspension solution in the same preparation condition in the embodiment 1; changing the ratio of the adding mass of the fully vulcanized nitrile rubber powder particles to the total mass of the mixed suspension solution; the ratio of the added mass of the polystyrene-acrylate to the total mass of the mixed suspension solution was changed to obtain examples 1-1 and 1-2.
Wherein, in comparative example 1-1, the added mass of the zeolite particles was 50% of the total mass of the mixed suspension solution; the adding mass of the fully vulcanized nitrile rubber powder particles is 5 percent of the total mass of the mixed suspension solution; the added mass of the polystyrene-acrylate is 5% of the total mass of the mixed suspension solution. In the suspension, the mass of solids was 60% of the total mass of the mixed suspension.
Wherein, in comparative examples 1-2, the added mass of the zeolite particles was 15% of the total mass of the mixed suspension solution; the adding mass of the fully vulcanized nitrile rubber powder particles is 1.5 percent of the total mass of the mixed suspension solution; the added mass of the polystyrene-acrylate was 1.5% of the total mass of the above mixed suspension solution. In the suspension, the mass of solids was 18% of the total mass of the mixed suspension.
4. Examples 1-5 impact resistance test
Drop tests were performed on the sound-absorbing microsphere materials prepared in examples 1 to 5. The drop test is as follows:
1) 0.1g of the sound-absorbing microsphere material prepared in examples 1 to 5 was loaded as a test sample into the back cavity of a micro-speaker, wherein the volume of the back cavity of the speaker was 1.0 cc.
2) The speaker was assembled in an aluminum alloy box with a size of 150 × 75 × 10mm (to simulate the environment in which the sound absorbing particulate material would be used in a cell phone), and 150g was weighed for each dropped test specimen.
3) The test specimen was lifted to a drop height of 1500mm (drop height means the distance between the lowest point of the specimen and the impact table in preparation for release) and supported in a predetermined state. Wherein the difference between the lifting height and the predetermined height is not more than + -2% of the predetermined height.
4) Selecting the longest edge and the largest surface of the aluminum alloy box as a drop test object; according to a preset state of one corner, three corners and six sides, the corner, the edge and the face fall (the corner, the edge and the face fall are respectively measured once to form a group of experiments), wherein the following conditions are required to be met when the face falls:
(a) when the angle falls, the error of the included angle between the specified surface of the test sample and the impact table surface is not more than +/-5 degrees or 10 percent (based on a larger numerical value) of the included angle, so that the gravity line of the test sample passes through the fallen angle;
(b) when the arris fall, the included angle between the falling arris and the horizontal plane is not more than 2 degrees at most, and the error of the included angle between the specified surface on the test sample and the impact table surface is not more than +/-5 degrees or 10 percent (based on a larger numerical value) of the included angle, so that the gravity line of the test sample passes through the falling arris;
(c) when the surface falls, the included angle between the falling surface of the test sample and the horizontal plane is not more than 2 degrees to the maximum; so that the line of gravity of the test sample passes through the dropped face;
(d) the difference between the actual impact speed and the impact speed in the free fall is not more than +/-1% of the impact speed in the free fall.
5. Impact resistance test of control group without adding rubber powder particles
The comparative examples, in which no rubber powder particles were added, were subjected to the impact resistance test in the same manner as described above.
6. Examples 1-5 resonant frequency testing
When the prepared zeolite particles are applied to a loudspeaker box, taking the volume of a rear cavity of a loudspeaker box tool as 1.0 cubic centimeter as an example, the size and the resonance frequency reduction value of the molded zeolite particles are reduced.
7. Resonance frequency test of control group without adding rubber powder particles
The resonance frequency test was performed on comparative example 1, comparative example 2, comparative example 3, comparative example 4 and comparative example 5, respectively, in the same manner as described above.
8. The values of the decrease in the resonance frequency and the results of the experiment of dropping were recorded for each example group sample after dropping and for the control group sample without adding rubber powder particles, and the recorded results are shown in table 1.
TABLE 1
9. The sound-absorbing microsphere materials prepared in example 1 and comparative examples 1 to 1 and 1 to 2 were subjected to the morphological analysis, and the resonance frequency reduction value and the drop test result were recorded, respectively, and the analysis and the recording results are shown in the following table.
TABLE 2
Based on the test results shown in the above table 1 and table 2, the inventors found that:
in the drop test, examples 1 to 5 were able to obtain intact microspheres, with only a small amount of powder, not a large amount of breakage, even if the microspheres were broken, relative to comparative examples 1 to 5, which indicates that: elastomer powder is introduced in the preparation process as a structural mechanical buffer filler, so that the problem of low impact toughness of the sound absorption microsphere material can be solved.
In example 1, when preparing a mixed suspension (also referred to as slurry), the addition amounts of the zeolite particle raw material, the fully vulcanized styrene-butadiene rubber powder particles and the polystyrene-acrylate adhesive are optimized to obtain the sound absorbing material with good microsphere morphology, and when the microsphere material is applied to the resonance frequency reduction value and the drop test analysis, better test results are obtained compared with comparative examples 1-1 and 1-2, because the solid content of the mixed suspension affects the microsphere morphology and the bulk density of the microsphere particles obtained by the spray drying granulation method.
Further, in this embodiment, the total mass of the solids added to the zeolite particles, the elastomer powder and the adhesive is preferably, and the total mass of the solids added to the zeolite particles, the elastomer powder and the adhesive is the total mass of the suspension: 25 to 50% by weight, because the granulation process of the sound-absorbing microspheres is considered, for example, the spray drying granulation method is preferable in this embodiment. When the size of the atomizer part of the spraying equipment is fixed, the higher the solid content in the suspension is, the higher the viscosity of the suspension is, the more difficult the atomizer is to atomize the suspension, the particles of the prepared microsphere material become non-uniform, and the yield of the product is reduced; in addition, the larger the solid content in the suspension is, the larger the particle bulk density of the prepared microsphere material is, and although the mechanical strength is improved, the specific surface area is reduced, and the acoustic effect is reduced. The smaller the solid content of the suspension is, the smaller the particle bulk density of the prepared microsphere material is, the loose microspheres are broken, the particles are smaller, and the mechanical impact resistance of the microspheres is influenced.
The present invention is made with respect to the diameter of the intrinsic pores of the zeolite particle raw material, preferably the diameter of the zeolite particles is 0.4nm to 0.6nm, which is preferable because, in general, the smaller the diameter of the intrinsic pores, the better the sound absorption performance, since sound is propagated by air vibration and the air is mainly composed of nitrogen, the lower limit of the intrinsic pore diameter of the selected zeolite is given by the kinetic diameter of nitrogen molecules (about 0.36 nm). further, the gas compliance of the material also directly affects the sound absorption performance, for example, the sound absorption performance is rather poor for DDR zeolite having a pore diameter of 0.44nm × 0.36.36 nm due to the problem of gas compliance, and therefore, it is very important to select an appropriate pore diameter, preferably 0.4nm to 0.6nm in the present example, according to the experimental results.
The present invention is preferably carried out with respect to the particle diameter of the crosslinked rubber having a high elasticity, and the particle diameter of the crosslinked rubber is preferably 50nm to 500nm, because: 1. because the crosslinked rubber has stronger elasticity, the smaller the particle, the larger the internal stress is, the small particle rubber powder is easy to break and can not keep the spherical shape, and the self is difficult to synthesize and process. In addition, the small rubber powder can block the surface pore channels of zeolite raw material particles, reduce the integral specific surface area and air smoothness of the microsphere material and is unfavorable for sound absorption performance. 2. The larger the rubber powder particles are, the more difficult the rubber powder particles are to be filled into gaps of zeolite particles (the particle diameter of the raw material of the zeolite particles is 0.5-5 μm, preferably 1-3 μm), the smaller the increase of the stacking density of the microsphere material is, and according to experimental results, the improvement of the mechanical impact resistance reflected by the prepared microsphere material is not obvious.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (10)
1. The preparation method of the sound-absorbing microsphere material is characterized by comprising the following steps of:
stirring zeolite particles, elastomer powder, an adhesive and solvent water to obtain a mixed suspension solution, wherein the adding mass of the elastomer powder is 2-4% of the total mass of the mixed suspension solution, and the total mass of solids added by the zeolite particles, the elastomer powder and the adhesive is the total mass of the mixed suspension solution: 25-50%;
and carrying out spray drying granulation and screening on the mixed suspension solution to obtain the sound absorption microsphere material with the target particle size.
2. The preparation method according to claim 1, wherein the granulating and screening of the mixed suspension solution to obtain the sound-absorbing microsphere material with a target particle size specifically comprises:
carrying out spray drying granulation on the mixed suspension solution to obtain primary formed particles;
drying the preliminarily molded particles for 1-3 h at 100-150 ℃ to obtain dried particles;
and screening the dry particles by using a screen to obtain the sound absorption microsphere material with the target particle size.
3. The method according to claim 2, wherein the target particle size is 150 to 380 μm.
4. The production method according to claim 1, wherein the added mass of the elastomer powder is 2.5 to 3.5% of the total mass of the mixed suspension solution.
5. The method according to claim 1, wherein the raw material of zeolite particles has a particle diameter in the range of 0.5 to 5 μm.
6. The method according to claim 5, wherein the raw material of zeolite particles has a particle diameter in the range of 1 to 3 μm.
7. The method of claim 1, wherein the elastomer powder is made of one or more of the following cross-linked rubbers:
crosslinked natural rubber, crosslinked butadiene rubber, crosslinked carboxylated styrene-butadiene rubber, crosslinked polybutadiene rubber, crosslinked nitrile rubber, crosslinked carboxylated nitrile rubber, crosslinked chloroprene rubber, crosslinked acrylate rubber, crosslinked silicone rubber and crosslinked butadiene-pyridine rubber.
8. The production method according to claim 1, wherein the elastomer powder has a particle diameter of 20nm to 2 μm.
9. The method according to claim 8, wherein the elastomer powder has a particle diameter of 50 to 500 nm.
10. A sound absorbing microsphere material prepared by the method of any one of claims 1 to 9.
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| CN109735116B (en) * | 2019-01-04 | 2021-03-30 | 山西大学 | Oil stain cleaning cotton and preparation method thereof |
| CN110012412B (en) * | 2019-04-24 | 2023-10-27 | 东莞顺合丰电业有限公司 | Sound absorbing particles, method for producing same, and speaker structure |
| CN113041993B (en) * | 2019-12-26 | 2024-01-23 | 镇江贝斯特新材料有限公司 | Zeolite ball type porous sound absorbing particles and application thereof in mobile phone loudspeaker system |
| CN111849048B (en) * | 2020-07-23 | 2022-04-12 | 陕西师范大学 | Metal powder-rubber particle composite phononic material, preparation method and application |
| CN113060975B (en) * | 2021-03-26 | 2022-08-02 | 镇江贝斯特新材料有限公司 | Low-temperature-resistant sound-absorbing material and preparation method and application thereof |
| CN113060976B (en) * | 2021-03-26 | 2022-09-30 | 镇江贝斯特新材料有限公司 | High-temperature-resistant sound-absorbing material and preparation method and application thereof |
| CN116161896A (en) * | 2021-11-25 | 2023-05-26 | 镇江贝斯特新材料股份有限公司 | Antistatic sound absorbing material, preparation method thereof, loudspeaker and electronic equipment |
| CN114505062A (en) * | 2022-01-26 | 2022-05-17 | 瑞声光电科技(常州)有限公司 | Gas adsorption material, preparation method thereof and loudspeaker box using gas adsorption material |
| CN115093159B (en) * | 2022-07-04 | 2023-07-04 | 瑞声科技（南京）有限公司 | Sound-absorbing material block, preparation method thereof and related equipment |
| CN115925320A (en) * | 2023-02-03 | 2023-04-07 | 德阳展源新材料科技有限公司 | Preparation method of efficient acoustic enhancement material |
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