KR102505292B1 - Optimal nanomaterial impregnation structure for improving sound absorption coefficient of porous sound absorbing materials - Google Patents

Abstract

The present invention relates to a porous sound absorbing material having an optimal nanomaterial impregnation structure and a manufacturing method thereof, and more particularly, to a porous member; It relates to a porous sound absorbing material having an optimal nanomaterial impregnated structure, characterized in that it comprises; and a nanomaterial impregnated into the porous member.

Description

Porous sound absorbing material having nanomaterial impregnated structure and manufacturing method thereof {Optimal nanomaterial impregnation structure for improving sound absorption coefficient of porous sound absorbing materials}

The present invention relates to a porous sound absorbing material having an optimal nanomaterial impregnation structure and a manufacturing method thereof.

Recently, interest in sound-absorbing materials has increased in order to improve comfort in living spaces and spaces within a means of transportation, and research to improve sound-absorbing performance continues.

As a sound-absorbing material, urethane, which can easily control hardness and minimize the emission of harmful substances, is in the limelight.

Urethane foam has a low density and sound absorption properties by having a porous structure, and can be prepared by mixing a polymer polyol, additives, and fillers using a mold or a foaming machine.

When conventional urethane foam is used as a sound-absorbing material, the thickness is generally increased, but in this case, weight and cost are increased.

Also, graphene is one of the carbon allotropes composed of carbon atoms. In general, graphene refers to a two-dimensional single sheet made of sp2 hybrids of carbon. Compared to other conventional nano additives (Na-MMT, LDH, CNT, CNF, EG, etc.), graphene has a large surface area, excellent mechanical strength, thermal and electrical properties, and flexibility and transparency. . Therefore, currently, research is being actively conducted to develop a high-performance functional polymer composite material having excellent conductivity and mechanical strength by filling a polymer resin with graphene (Polymer Science and Technology Vol 22, No 5, October 2011).

A porous structure is mainly used as a material for damping noise and vibration. Depending on the cell size or shape of this porous structure, the vibration damping properties appear differently. Among the porous structures, when an organic porous structure having a negative Poisson's ratio is used, a general circular unit cell structure is twisted and the wire is bent in an irregular shape. Accordingly, a structure characterized by a negative Poisson's ratio is formed, and impact and vibration damping properties are improved due to an effective local compression strengthening effect of impact energy during tension-compression deformation. As a result, research on practical engineering applications of organic porous structures is emerging (ACS Appl Mater Interfaces, Vol 10, No 26, May 2018).

Japanese Patent Publication JP2020-512436A Republic of Korea Patent Publication KR2021-0004372A Republic of Korea Patent Publication KR2018-0020010A Republic of Korea Patent Publication KR 2020-0078247A

Therefore, the present invention has been made to solve the above conventional problems, and according to an embodiment of the present invention, when impregnating a two-dimensional nanomaterial such as graphene oxide into a porous material similar to a conventional polyurethane foam form, The purpose is to provide a porous sound absorbing material having an optimal nanomaterial impregnated structure and a method for manufacturing the same, which can minimize the use of nanomaterials and maximize the improvement of sound absorption performance by impregnating with an optimal structure rather than impregnating with a simple structure. there is.

When the impregnation structure according to the embodiment of the present invention is applied, the low-frequency sound absorption can be greatly improved, and by utilizing the non-contact vacuum impregnation technology, the nanomaterial can be impregnated without structural damage to the inside, and the vacuum impregnation technology When used, almost no external force is applied to the porous material, so a specific nanomaterial can be located in the porous material without damage, and the optimal impregnation structure for nanomaterials can reduce the use of nanomaterials and maximize sound absorption performance through impregnation optimization. Its purpose is to provide a porous sound absorbing material having and a manufacturing method thereof.

According to an embodiment of the present invention, it can be used to improve the sound absorption coefficient of polyurethane foam, which is a sound absorbing member, through the vacuum impregnation method, and can be used to adjust the modulus of elasticity and heat transfer of other porous materials, and can be used to adjust the size of the porous material. The purpose is to provide a porous sound absorbing material having an optimal nanomaterial impregnated structure and a method for manufacturing the same, which can be used even for large porous materials when a jig is made to fit.

In addition, according to an embodiment of the present invention, since the acoustic properties of polyurethane foam can be adjusted to the desired performance, the polyurethane foam made through the impregnation process can be used in a sound studio, etc., and can be impregnated uniformly and evenly regardless of size. Therefore, the purpose is to provide a porous sound absorbing material having an optimal nanomaterial impregnated structure and a method for manufacturing the same, which can be used for manufacturing a large sound absorbing material and can be used in the railway and automobile fields where noise must be reduced by applying a new impregnation technology.

On the other hand, the technical problems to be achieved in the present invention are not limited to the above-mentioned technical problems, and other technical problems that are not mentioned will become clear to those skilled in the art from the description below. You will be able to understand.

A first object of the present invention, in the sound absorption material, a porous member; It can be achieved as a porous sound absorbing material having an optimal nanomaterial impregnation structure, characterized in that it comprises; and nanomaterial impregnated into the porous member.

Further, when the thickness of the porous member is equal to or less than the first specific thickness, the density of the nanomaterial may be maximum at the side of the sound wave incident surface.

In addition, when the thickness of the porous member is greater than or equal to the second specific thickness, the density of the nanomaterial may be maximum on a surface opposite to the incident surface of the sound wave.

And, when the thickness of the porous member is greater than the first specific thickness and less than the second specific thickness, the portion where the density of the nanomaterial is maximized is proportional to the thickness of the porous member, from the side of the incident surface of the sound wave to the opposite surface of the incident surface. It may be characterized in that it is moved to the side.

In addition, vacuum impregnation is applied in which the porous member soaked in the nanomaterial solution containing the nanomaterial is inserted into the open surface of the vacuum chamber, and the nanomaterial is impregnated into the porous member by vacuuming the inside of the vacuum chamber. can be done with

And it may be characterized in that the content density and elastic modulus increase in proportion to the number of times of vacuum impregnation.

In addition, the first specific thickness may be 20 to 30 mm, and the second specific thickness may be 40 to 50 mm.

The porous member may be configured by being stacked in a plurality of layers, and when the total thickness of the stacked porous members is equal to or less than the first specific thickness, the number of times of impregnation of the layer on the side of the incident surface of the sound wave may be maximum.

In addition, when the total thickness of the stacked porous members is greater than or equal to the second specific thickness, the number of impregnations may be maximum in the layer on the side opposite to the incident surface of the sound wave.

And when the total thickness of the stacked porous members exceeds the first specific thickness and is less than the second specific thickness, the layer having the maximum number of times the nanomaterials are included is incident from the side of the incident surface of the sound wave in proportion to the thickness of the porous member. It may be characterized in that it is moved to the side opposite the surface.

In addition, the nanomaterial may be graphene oxide, and the porous member may be characterized in that polyurethane foam.

A second object of the present invention is a method for producing a sound absorbing material, comprising: preparing a porous member having a specific thickness; Wetting the porous member with a nanomaterial solution containing nanomaterials; and inserting the porous member into the open surface of the vacuum chamber, and impregnating the nanomaterial into the porous member by setting the inside of the vacuum chamber to a vacuum state. It can be achieved as a manufacturing method of.

A third object of the present invention is a method for producing a sound absorbing material, comprising: preparing a plurality of porous member layers having a specific thickness; Wetting each of the plurality of porous member layers with a nanomaterial solution containing nanomaterials; inserting each of the porous member layers into an open surface of a vacuum chamber, and impregnating the nanomaterial into each of the porous member layers by vacuuming the inside of the vacuum chamber; It can be achieved as a method for manufacturing a porous sound absorbing material having an optimal nanomaterial impregnation structure, characterized in that it includes; and stacking and combining the porous member layers.

And it may be characterized in that the porous member layer is impregnated with nanomaterials at different impregnation times to have different containing densities.

In addition, when the total thickness of the stacked porous members is equal to or less than the first specific thickness, the number of impregnations of the layer on the side of the sound wave incident surface is maximum, and when the total thickness of the stacked porous members is equal to or greater than the second specific thickness, the incident face of the sound wave It may be characterized in that the number of impregnations of the layer on the opposite side of the is maximum.

And when the total thickness of the stacked porous members exceeds the first specific thickness and is less than the second specific thickness, the layer having the maximum number of times the nanomaterials are included is incident from the side of the incident surface of the sound wave in proportion to the thickness of the porous member. It may be characterized in that it is moved to the side opposite the surface.

According to the porous sound absorbing material having the optimal nanomaterial impregnation structure and the manufacturing method according to an embodiment of the present invention, when a two-dimensional nanomaterial such as graphene oxide is impregnated into a porous material similar to a conventional polyurethane foam, it has a simple structure. It has an effect of minimizing the use of nanomaterials and maximizing the improvement of sound absorption performance by impregnating with an optimal structure rather than impregnation.

When the impregnation structure according to the embodiment of the present invention is applied, the low-frequency sound absorption can be greatly improved, and by utilizing the non-contact vacuum impregnation technology, the nanomaterial can be impregnated without structural damage to the inside, and the vacuum impregnation technology When used, almost no external force is applied to the porous material, so a specific nanomaterial can be placed in the porous material without damage, and through impregnation optimization, the use of nanomaterials can be reduced and the sound absorption performance can be improved to the maximum.

According to the porous sound absorbing material having an optimal nanomaterial impregnated structure and the manufacturing method thereof according to an embodiment of the present invention, it can be used to improve the sound absorption coefficient of polyurethane foam, which is a sound absorbing member, through the vacuum impregnation method, and the elastic modulus of other porous materials It can be used to control and heat transfer, and when the jig is made according to the size of the porous material, it can be used for large porous materials.

And according to the porous sound absorbing material having an optimal nanomaterial impregnated structure and its manufacturing method according to an embodiment of the present invention, since the acoustic properties of polyurethane foam can be adjusted as much as the desired performance, the polyurethane foam made through the impregnation process is used in the sound workroom. It can be used in the back, etc., and can be impregnated consistently and evenly regardless of size, so it can be used for making large sound absorbers, and it has the advantage of being used in the railway and automobile fields where noise must be reduced by applying a new impregnation technology.

On the other hand, the effects obtainable in the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below. You will be able to.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the present invention, so the present invention is limited only to those described in the drawings. and should not be interpreted.
1 is a graph of sound absorption coefficient for each frequency according to the number of nanomaterial impregnations;
2 is a graph of tortuosity according to the density of nanomaterials;
3 is a table of changes in mechanical properties of porous members with respect to the number of impregnations;
Figure 4 is simulation data for the content density by thickness of the porous member according to an embodiment of the present invention,
Figure 5 is a graph of the average sound absorption rate for the measured value and expected height for each thickness according to an embodiment of the present invention;
6 is a graph of the sound absorption coefficient by frequency when graphene oxide is impregnated to have a small-mil content density for a porous member having a thickness of 56 mm according to an embodiment of the present invention;
7a is a cross-sectional view of a sound absorbing material having a thickness equal to or less than a first specific thickness according to an embodiment of the present invention;
7B is a cross-sectional view of a sound absorbing material having a thickness greater than a first specific thickness and less than a second specific thickness according to an embodiment of the present invention;
7c is a cross-sectional view of a sound absorbing material having a thickness greater than or equal to a second specific thickness according to an embodiment of the present invention;
8 is a comparison table of non-destructive vacuum impregnation according to an embodiment of the present invention and an impregnation method through conventional physical compression;
Figure 9a is a photograph of the progress of impregnation through conventional physical compression;
Figure 9b is a photograph of the progress of non-destructive vacuum impregnation according to an embodiment of the present invention;
Figure 10a is a graph of the amount of impregnation according to the number of times of impregnation according to an embodiment of the present invention;
Figure 10b is a graph of elastic modulus according to the amount of impregnation according to an embodiment of the present invention;
11 is a flow chart for manufacturing a layered sound absorbing material according to an embodiment of the present invention;
12 is a flow chart of a vacuum impregnation method according to an embodiment of the present invention;
13 is a photograph of the sound absorbing material by number of impregnations according to an embodiment of the present invention;
14A is a cross-sectional view of a sound absorbing material in the form of a layered stack in the case of having a thickness equal to or less than a first specific thickness according to an embodiment of the present invention;
14b and 14c are cross-sectional views of a sound absorbing material in the form of a layered stack in the case of having a thickness greater than a first specific thickness and less than a second specific thickness according to an embodiment of the present invention;
FIG. 14D is a cross-sectional view of a sound absorbing material in the form of a stacked layer in the case of having a thickness greater than or equal to a second specific thickness according to an embodiment of the present invention.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete and the spirit of the present invention will be sufficiently conveyed to those skilled in the art.

In this specification, when an element is referred to as being on another element, it means that it may be directly formed on the other element or a third element may be interposed therebetween. Also, in the drawings, the thickness of components is exaggerated for effective description of technical content.

Embodiments described in this specification will be described with reference to cross-sectional views and/or plan views, which are ideal exemplary views of the present invention. In the drawings, the thicknesses of films and regions are exaggerated for effective explanation of technical content. Accordingly, the shape of the illustrated drawings may be modified due to manufacturing techniques and/or tolerances. Therefore, embodiments of the present invention are not limited to the specific shape shown, but also include changes in the shape generated according to the manufacturing process. For example, a region shown at right angles may be rounded or have a predetermined curvature. Accordingly, the regions illustrated in the drawings have attributes, and the shapes of the regions illustrated in the drawings are intended to illustrate a specific shape of a region of a device and are not intended to limit the scope of the invention. Although terms such as first and second are used to describe various elements in various embodiments of the present specification, these elements should not be limited by these terms. These terms are only used to distinguish one component from another. Embodiments described and illustrated herein also include complementary embodiments thereof.

Terminology used herein is for describing the embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. The terms 'comprises' and/or 'comprising' used in the specification do not exclude the presence or addition of one or more other elements.

In describing the specific embodiments below, several specific contents are prepared to more specifically describe the invention and aid understanding. However, readers who have knowledge in this field to the extent that they can understand the present invention can recognize that it can be used without these various specific details. In some cases, it is mentioned in advance that parts that are commonly known in describing the invention and are not greatly related to the invention are not described in order to prevent confusion for no particular reason in explaining the present invention.

Hereinafter, the configuration, function, and manufacturing method of the porous sound absorbing material having an optimal nanomaterial impregnation structure according to an embodiment of the present invention will be described.

A porous sound absorbing material having an optimal nanomaterial impregnation structure according to an embodiment of the present invention includes a porous member and a nanomaterial impregnated into the porous member.

The porous member according to an embodiment of the present invention may be polyurethane foam, and the nanomaterial may be composed of graphene oxide.

First, FIG. 1 shows a graph of the sound absorption coefficient for each frequency according to the number of nanomaterial impregnations. And FIG. 2 shows a graph of tortuosity according to the nanomaterial content density, and FIG. 3 shows a table of changes in mechanical properties of the porous member with respect to the number of impregnations.

As shown in FIG. 1, the absorption rate for low frequencies increases as the number of impregnations of graphene oxide into the porous member increases, but as shown in FIGS. 2 and 3, structural damage inside the porous member may exist. it can be seen that there is

According to the sound absorbing material having an optimal nanomaterial impregnation structure and the manufacturing method according to an embodiment of the present invention, when a two-dimensional nanomaterial such as graphene oxide is impregnated into a porous material similar to a conventional polyurethane foam, it is impregnated with a simple structure. As described later than in the case of using nanomaterials, it is possible to minimize the use of nanomaterials and maximize the improvement of sound absorption performance by impregnating them in an optimal structure, and by utilizing non-contact vacuum impregnation technology, nanomaterials can be produced without internal structural damage. When vacuum impregnation technology is used, almost no external force is applied to the porous material, so specific nanomaterials can be located in the porous material without damage. be able to do

Figure 4 shows simulation data for the content density of each thickness of the porous member according to an embodiment of the present invention, Figure 5 shows a graph of the average sound absorption rate for the measured value and expected value for each thickness according to an embodiment of the present invention , Figure 6 shows a graph of sound absorption coefficient for each frequency in the case of impregnating graphene oxide to have a low-mil content density for a porous member having a thickness of 56 mm according to an embodiment of the present invention.

The average sound absorption coefficient is expressed by Equation 1 below.

[Equation 1]

7A is a cross-sectional view of a sound absorbing material having a thickness equal to or less than a first specific thickness according to an embodiment of the present invention. 7B is a cross-sectional view of a sound absorbing material having a thickness greater than the first specific thickness and less than the second specific thickness according to an embodiment of the present invention. And Figure 7c shows a cross-sectional view of the sound absorbing material in the case of having a thickness equal to or greater than the second specific thickness according to an embodiment of the present invention.

When the thickness of the porous member 10 according to an embodiment of the present invention is less than or equal to the first specific thickness, the density of the nanomaterial 20 is greatest on the side of the sound wave incident surface 2, and gradually increases along the sound wave traveling direction. It is configured to be small as .

This first specific thickness may vary depending on the type of porous member 10, but may be, for example, 20 to 30 mm.

7A and 4, the first and second sound absorbing materials 100 having a thickness equal to or less than the first specific thickness, the density of nanomaterials on the incident surface 2 of the sound wave is maximized, and the sound wave progresses. It can be seen that the structure is configured so that the containing density gradually decreases in the direction (from the incident surface to the wall 1 side).

In addition, when the thickness of the porous member 10 is greater than or equal to the second specific thickness, the density of the nanomaterial 20 gradually increases along the traveling direction of the sound wave, and the surface opposite to the incident surface 2 of the sound wave (wall 1 ) side) is configured to be maximum in

For example, this second specific thickness may be 40 to 50 mm, and the first and second right sides of FIGS. 7C and 4 are sound absorbing materials 100 having a thickness greater than or equal to the second specific thickness, opposite to the sound wave incident surface 2. The density of the nanomaterial 20 is maximized on the surface (the surface of the wall (1)), and the density is gradually decreased in the opposite direction of the sound wave (from the side of the wall (1) to the side of the incident surface (2)). composition can be seen.

And, when the thickness of the porous member 10 exceeds the first specific thickness and is less than the second specific thickness, the portion where the density of the nanomaterial 20 is maximized is proportional to the thickness of the porous member 10, and the incident surface of the sound wave It is moved from the (2) side to the opposite side of the incident surface (wall (1)), and the content density is gradually reduced on both sides of the incident surface (2) and the opposite surface (wall (1)) based on the maximum content density. do.

The third and fourth from the right of FIGS. 7B and 4 are sound absorbing materials 100 having a thickness greater than the first specific thickness and less than the second specific thickness, with the maximum content density in the middle portion, and the incident surface 2 and the wall 1 ), it can be seen that the content density is gradually reduced on each side of the surface.

In addition, within this range, as shown in FIG. 4, it can be seen that the portion where the content density is maximized in proportion to the thickness of the porous member 10 is moved from the sound wave incident surface 2 side to the wall 1 side. there is.

As shown in FIG. 6, when the content density is gradually increased from the incident surface 2 side to the wall 1 side for the sound absorbing material 100 having a thickness of 56 mm or more, that is, the second specific thickness, the maximum average sound absorption coefficient is 0.9011 It can be seen that this is derived.

In addition, in the embodiment of the present invention, a vacuum impregnation method, rather than physical compression, is applied as an impregnation method of graphene oxide, which is a nanomaterial. Therefore, when vacuum impregnation technology is used, almost no external force is applied to the porous material, so specific nanomaterials can be located in the porous material without damage, and the vacuum impregnation method can be used to improve the sound absorption coefficient of polyurethane foam, which is a porous member. And, it can be used to adjust the modulus of elasticity and heat transfer of other porous materials, and when a jig is made to fit the size of the porous material, it can be used for large porous materials.

8 shows a comparison table of non-destructive vacuum impregnation according to an embodiment of the present invention and an impregnation method through conventional physical compression. Figure 9a shows a picture of the progress of impregnation through conventional physical compression, and Figure 9b shows a picture of the progress of non-destructive vacuum impregnation according to an embodiment of the present invention. 10A shows a graph of the amount of impregnation according to the number of times of impregnation according to an embodiment of the present invention. 10B shows a graph of elastic modulus according to the amount of impregnation according to an embodiment of the present invention.

As shown in FIG. 8, it can be seen that the application of the vacuum impregnation method can shorten the impregnation time, finely adjust the amount of impregnation, and control the acoustic performance and modulus of elasticity.

That is, as shown in FIGS. 10A and 10B, since the amount of graphene oxide impregnated increases in direct proportion to the number of times of vacuum impregnation, the porous member 10 can be accurately impregnated with the nanomaterial 20 to a desired density. , it is possible to control the sound absorption coefficient and elastic modulus according to the desired value.

In addition, in an embodiment of the present invention, a sound absorbing material may be manufactured by impregnating nanomaterials into each of a plurality of porous member layers and then stacking porous member layers impregnated with nanomaterials.

11 shows a flow chart for manufacturing a layered sound absorbing material according to an embodiment of the present invention. And FIG. 12 shows a flow chart of a vacuum impregnation method according to an embodiment of the present invention, and FIG. 13 shows a picture of a sound absorbing material according to the number of times of impregnation according to an embodiment of the present invention.

14A is a cross-sectional view of a sound absorbing material having a thickness equal to or less than a first specific thickness according to an embodiment of the present invention, and FIGS. 14B and 14C show a first specific thickness according to an embodiment of the present invention. It is a cross-sectional view of a sound absorbing material in the form of a layered layer in the case of having a thickness greater than or less than the second specific thickness, and FIG. A cross section is shown.

First, a plurality of porous member layers 11 having a specific thickness are prepared.

A nanomaterial 20 such as graphene oxide is impregnated into each of the plurality of porous member layers 11 by a vacuum impregnation method. By varying the number of times of impregnation for each porous member layer 11, the content density may be different.

In the vacuum impregnation method, as shown in FIG. 12, the nanomaterial solution 21 (eg, graphene oxide solution) containing the nanomaterial 20 is wetted in the porous member layer 11, and the nanomaterial solution ( 21) is inserted into the open surface 31 of the vacuum chamber 30, and the inside of the vacuum chamber 30 is vacuumed through the suction port 33 after the lid 32 is closed. Thus, the nanomaterial 20 is impregnated into each porous member layer 11 .

The impregnation amount of the nanomaterial 20 in each porous member layer 11 may be adjusted in proportion to the number of such vacuum impregnation processes.

Then, the porous member layers 11 having different impregnation counts (containing densities) are stacked according to the total thickness of the sound absorbing material 100 to be manufactured, so that the sound absorbing material is finally manufactured.

That is, as shown in FIG. 14A, when the total thickness of the sound absorbing material 100 on which the layers 11 are stacked is less than or equal to the first specific thickness, the number of impregnations of the layer 11 on the side of the incident surface 2 of the sound wave is maximum, and , It is configured so that the number of impregnations gradually decreases along the traveling direction of the sound wave. For example, when the total thickness of the sound absorbing material 100 formed by stacking six layers 11 is less than or equal to the first specific thickness (for example, 12 mm), the maximum number of impregnations is, for example, 6 impregnations of nanomaterials. This impregnated layer is placed on the side of the sound wave incident surface, and a layer having 5 impregnations in the sound wave propagation direction, a layer having 4 impregnations, a layer having 3 impregnations, a layer having 2 impregnations, 1 It is possible to manufacture a scratch material by stacking layers having the number of times of impregnation.

In addition, as shown in FIG. 14D, when the total thickness of the sound absorbing material 100 in which the layers 11 are stacked is equal to or greater than the second specific thickness, the number of impregnations of nanomaterials for each layer 11 gradually increases along the traveling direction of the sound wave. and the number of impregnations can be maximized on the surface opposite to the incident surface 2 of the sound wave (the surface of the wall 1). For example, when the total thickness of the sound absorbing material 100 composed of six layers is laminated is greater than the second specific thickness (eg, 60 mm), the number of impregnations is maximum, for example, nanomaterials are impregnated with the number of impregnations of 6 times. Place the layer on the opposite side of the sound wave (the wall 1 side), and in the opposite direction of the sound wave, a layer with 5 impregnations, a layer with 4 impregnations, a layer with 3 impregnations, and 2 impregnations A layer having a number of times and a layer having a number of impregnations of 1 may be stacked to manufacture a scratched material.

In addition, when the total thickness of the sound absorbing material 100 in which the layers 11 are stacked is greater than the first specific thickness and less than the second specific thickness, the layer 11 having the maximum number of nanomaterials contained is in proportion to the thickness of the porous member. The sound waves are moved from the incident surface (2) side to the wall (1) side, and the number of impregnations gradually decreases on both sides of the incident surface (2) and the wall (1) surface based on the layer (11) with the maximum number of contents. can be configured.

For example, as shown in FIG. 14B, when the total thickness of the sound absorbing material composed of the stacked six layers exceeds the first specific thickness and is less than the second specific thickness (for example, 30 mm), the maximum number of impregnations. For example, , The layer impregnated with nanomaterials with the number of impregnations of 6 is placed in the third part from the side of the sound wave incident surface, and based on this, the layer with the number of impregnation of 5 times, the layer with the number of impregnation of 4 times, and the layer with the number of impregnation of 4 times, A layer having the number of impregnations may be laminated, and a layer having the number of impregnation 5 times and a layer having the number of impregnation 4 may be laminated in the direction opposite to the propagation of the sound wave to manufacture a hollow material.

In addition, within the first specific thickness and less than the second specific thickness, the layer in which the number of impregnations is maximized in proportion to the total thickness of the sound absorbing material is moved from the sound wave incident surface side to the wall side. That is, for example, as shown in FIG. 14C, the total thickness of the sound absorbing material composed of six layers is greater than the first specific thickness and less than the second specific thickness, and is thicker than FIG. 14B (for example, 40 mm), The number of impregnations is maximum. For example, the layer impregnated with nanomaterials with the number of impregnations of 6 is placed in the 5th part from the side of the sound wave incident surface, and based on this, layers having the number of impregnations of 5 times are laminated in the direction of sound wave propagation, A layer having 5 impregnations, a layer having 4 impregnations, a layer having 3 impregnations, and a layer having 2 impregnations may be laminated in the opposite direction of sound wave propagation to produce a void material.

As mentioned above, according to the porosity having the optimal nanomaterial impregnation structure and the manufacturing method according to the embodiment of the present invention, two-dimensional nanomaterials such as graphene oxide can be impregnated into a porous material similar to the existing polyurethane foam form. When impregnating with an optimal structure, rather than impregnating with a simple structure, it is possible to minimize the use of nanomaterials and maximize the improvement of sound absorption performance.

In addition, when the impregnation structure according to the embodiment of the present invention is applied, the low-frequency sound absorption rate can be greatly improved, and by using the non-contact vacuum impregnation technology, the nanomaterial can be impregnated without structural damage to the inside, and the vacuum impregnation technology Since almost no external force is applied to the porous material when using, specific nanomaterials can be located in the porous material without damage. Through this, it can be used to improve the sound absorption coefficient of polyurethane foam, which is a sound absorbing member, and can be used to adjust the elastic modulus and heat transfer of other porous materials.

In addition, the device and method described above are not limited to the configuration and method of the above-described embodiments, but all or part of each embodiment is selectively combined so that various modifications can be made. may be configured.

1: wall
2: Sound wave incident plane
10: porous member
11: Layers
20: nanomaterial
21: nanomaterial solution
30: vacuum chamber
31: open side
32: lid
33: inlet
100: Porous sound absorbing material having an optimal nanomaterial impregnation structure

Claims (16)

In the sound absorbing material,
porous member; and a nanomaterial impregnated into the porous member.
The porous sound-absorbing material having a nanomaterial impregnated structure, characterized in that the content density of the nanomaterial is maximum on the side of the incident surface of the sound wave, or maximum on the surface opposite to the incident surface of the sound wave.
According to claim 1,
When the thickness of the porous member is less than or equal to the first specific thickness, the density of the nanomaterial is maximum on the side of the incident surface of the sound wave, and the first specific thickness is 20 to 30 mm. sound absorbing material.
According to claim 2,
When the thickness of the porous member is greater than or equal to the second specific thickness, the density of the nanomaterial is maximum on the surface opposite to the incident surface of the sound wave, and the second specific thickness is 40 to 50 mm. Porous sound absorbing material having.
According to claim 3,
When the thickness of the porous member is greater than the first specific thickness and less than the second specific thickness,
A porous sound-absorbing material having a nanomaterial impregnated structure, characterized in that the portion where the nanomaterial density is maximized is moved from the incident surface side of the sound wave to the opposite surface side of the incident surface in proportion to the thickness of the porous member.
According to claim 3,
Vacuum impregnation is applied in which the porous member soaked in the nanomaterial solution containing the nanomaterial is inserted into the open surface of the vacuum chamber, and the nanomaterial is impregnated into the porous member by vacuuming the inside of the vacuum chamber. A porous sound absorbing material having a nanomaterial impregnated structure.
According to claim 5,
A porous sound-absorbing material having a nanomaterial impregnated structure, characterized in that the content density and elastic modulus are increased in proportion to the number of times of vacuum impregnation.
delete According to claim 5,
The porous member is configured by being laminated in the form of a plurality of layers,
When the total thickness of the stacked porous members is less than or equal to the first specific thickness,
A porous sound absorbing material having a nanomaterial impregnated structure, characterized in that the number of impregnations of the layer on the side of the incident surface of the sound wave is maximum.
According to claim 8,
When the total thickness of the stacked porous members is equal to or greater than the second specific thickness,
A porous sound absorbing material having a nanomaterial impregnated structure, characterized in that the number of impregnations is maximum in the layer on the opposite side of the incident surface of the sound wave.
According to claim 9,
When the total thickness of the stacked porous members is greater than the first specific thickness and less than the second specific thickness,
A porous sound-absorbing material having a nanomaterial impregnated structure, characterized in that the layer having the maximum number of nanomaterials is moved from the incident surface side of the sound wave to the opposite surface side of the incident surface in proportion to the thickness of the porous member.
According to claim 1,
The nanomaterial is graphene oxide, and the porous member is a porous sound absorbing material having a nanomaterial impregnated structure, characterized in that polyurethane foam.
In the method for producing a sound-absorbing material,
preparing a porous member;
Wetting the porous member with a nanomaterial solution containing nanomaterials; and
Inserting the porous member into the open surface of the vacuum chamber, and impregnating the nanomaterial into the porous member by vacuuming the inside of the vacuum chamber; manufacturing a porous sound absorbing material having a nanomaterial impregnated structure, characterized in that it comprises a method.
In the method for producing a sound-absorbing material,
preparing a plurality of porous member layers;
Wetting each of the plurality of porous member layers with a nanomaterial solution containing nanomaterials;
inserting each of the porous member layers into an open surface of a vacuum chamber, and impregnating the nanomaterial into each of the porous member layers by vacuuming the inside of the vacuum chamber; and
Method for producing a porous sound-absorbing material having a nanomaterial impregnated structure, comprising: stacking and combining the porous member layers.
According to claim 13,
Method for producing a porous sound-absorbing material having a nanomaterial impregnated structure, characterized in that the porous member layer is impregnated with nanomaterials at different impregnation times to have different content densities.
According to claim 14.
When the total thickness of the stacked porous members is less than or equal to the first specific thickness,
The number of impregnations of the layer on the side of the incident surface of the sound wave is maximum,
When the total thickness of the stacked porous members is equal to or greater than the second specific thickness,
The number of impregnations of the layer on the side opposite to the incident surface of the sound wave is maximum,
The first specific thickness is 20 ~ 30mm, the second specific thickness is a method for producing a porous sound-absorbing material having a nanomaterial impregnated structure, characterized in that 40 ~ 50mm.
According to claim 15,
When the total thickness of the stacked porous members is greater than the first specific thickness and less than the second specific thickness,
Method for producing a porous sound absorbing material having a nanomaterial impregnated structure, characterized in that the layer in which the number of nanomaterials is contained is moved from the side of the incident surface of the sound wave to the opposite surface of the incident surface in proportion to the thickness of the porous member.

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