KR20150072555A - Dash inner insulation for vehicle - Google Patents

Abstract

An objective of the present invention is to provide dash inner insulation for a vehicle offering improved soundproofing and sound absorption while minimizing an increase in weight of polyurethane foam by changing the cell structure of polyurethane foam with carbon nanotube (CNT) added in manufacturing polyurethane foam which is a material used in dash inner insulation to mainly absorb sound. More specifically, the objective of the present invention is to provide dash inner insulation for vehicle with outstanding sound absorption compared to an increase in weight through a process of adding carbon nanotube to an undiluted solution of polyurethane foam while other processes remain the same as making conventional polyurethane foam.

Description

[0001] DASH INNER INSULATION FOR VEHICLE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile dash inner insulation, and more particularly, to a method of manufacturing a polyurethane foam by forming a polyurethane foam by changing the cell structure of a polyurethane foam by adding carbon nanotubes (CNTs) So that the increase in the weight of the urethane foam can be minimized and the suction and sound insulation performance can be improved.

Generally, as shown in FIG. 1, the noise felt in the interior of a vehicle is a noise that flows into the room through the dash panel at the engine room side of the vehicle and noise that flows into the room through the lower portion or the side of the interior of the vehicle, Can be largely divided. Accordingly, the vehicle is equipped with insulation (I) inside the dash panel (D) in order to block such noise.

Such noise is transmitted to the interior of the vehicle through the dash panel or the floor panel, thereby reducing the ride quality. Therefore, dash inner insulation is installed on the inside of the dash panel D, the floor panel, and the like so that the noise generated in the engine room and the noise generated in the bottom of the floor panel are not transmitted to the room side.

The dash inner insulation for blocking noise is manufactured using various materials and various materials as in the following Patent Documents 1 to 3.

Patent Document 1 describes a sound insulating system including a viscoelastic foam. The subtractive system includes a sound-absorbing layer. The sound-absorbing layer may include a viscoelastic foam. Any barrier layer is adjacent to the sound-absorbing layer. Also, any substrate layer is adjacent to the sound-absorbing layer, away from any barrier layer and on the opposite side. The car scale is particularly well suited for use as an automotive dash mat.

Patent Document 2 can effectively absorb the noise introduced into the vehicle room from the engine room and appropriately reduce the noise, improve the NVH (Noise, Vibration, Harshness) and merchantability of the vehicle, An upper panel having a panel structure in which an aluminum foil panel, a polyurethane foam panel and a nonwoven panel are sequentially stacked in three layers, and a nonwoven panel, a glass wool panel and a nonwoven panel are sequentially arranged in three layers And a lower panel coupled to the upper panel with a superimposed panel structure.

Patent Document 3 discloses a method of manufacturing an insulation using a hollow sound absorbing layer having pores and mounting the insulation on the inner side of the inner dash panel to thereby reduce noise through hollows formed in the hollow sound absorbing layer The present invention also provides a dash inner insulation for an automobile which is improved in sound absorption performance so that a heat insulating effect can be obtained simultaneously with a phenomenon such as an air layer.

However, in order to obtain sound absorption and sound insulation performance, such a conventional dash inner insulation is often formed by overlapping with a sound absorption layer and a sound insulation layer. In order to improve such a sound absorption performance and a sound insulation performance, the thickness of the corresponding layer must be made thick. Thus, although the intake and sound insulating performance can be improved, the weight of the dash inner insulation increases, which increases the fuel consumption, thereby deteriorating the energy efficiency.

Therefore, dash inner insulation which can increase the weight of the dash inner insulation while improving the weight of the dash inner insulation is required.

Korean Patent Laid-Open No. 10-2006-0123475 (published on December 1, 2006) Korean Registered Patent No. 1262609 (Registered on May 31, 2013) Korean Registered Patent No. 1317818 (Registered on July 10, 2013)

The present invention has been made in view of this point, and it is an object of the present invention to provide a polyurethane foam which is mainly used as a base material for dash inner insulation by adding carbon nanotubes (CNTs) It is an object of the present invention to provide a dash inner insulation for automobiles that can improve the absorption and sound insulation performance while minimizing the weight increase of the urethane foam.

In particular, the present invention relates to a process for producing such a polyurethane foam by a process similar to the production of a conventional polyurethane foam, wherein a carbon nano tube alone is added to a polyurethane foam raw solution, There are other purposes for providing insulation.

In order to achieve the above object, the automobile dash inner insulation according to the present invention is characterized in that a mixture of isocyanate (Isocyanate) having a weight ratio of 40 to 60 and carbon nanotubes having a weight ratio of 0.1 to 7.25 And then foamed polyurethane foam (100) after stirring.

In particular, a filler containing carbon nanotubes is added to the isocyanate / undiluted solution, and the mixture is stirred for 25 to 35 seconds, followed by further stirring for 6 to 10 seconds in addition to the polyol stock solution, followed by foaming. Here, the polyol has a weight ratio of 45.0 to 50.0 of a polymer PPG, 26.0 to 32.0 of a low molecular PPG, 2.0 to 4.0 of a cell opener, 3.0 to 5.0 of a chain extender, -retardant: 5.0 to 7.0, a silicone surfactant: 1.2 to 1.8, an amine catalyst: 0.8 to 1.2, and water: 6.0 to 9.0.

The carbon nanotubes may be single wall or multiple wall having a diameter of 10 to 50 nm, a bulk density of 0.02 to 1.50 g / ml, a purity of 85 to 90% and a crystallinity (I _G / I _D ) of 0.7 to 1.1, Or in the form of powder granules.

Also, the polyurethane foam 100 has a density of 50 to 130 kg / m 3.

In the preferred embodiment of the present invention, the automobile dash inner insulation is characterized in that at least one of the sound insulating layer 200 and the sound-absorbing layer 300 is provided on both sides.

Particularly, the sound insulating layer 200 is formed of at least one of ethylene vinyl acetate (EVA), thermo plastic elastomer (TPE), poly ethylene terephthalate (PET), natural rubber, and NDR (NOISE DAMPING RUBBER).

Finally, the sound-absorbing layer 300 is formed of at least one of PET (poly ethylene terephthalate) felt, PP (polypropylene) felt, nonwoven, glass wool, and resin felt. The nonwoven fabric may be a general nonwoven fabric, a reinforced nonwoven fabric, a water repellent nonwoven fabric, or a reinforced / foamed nonwoven fabric.

The automotive dash inner insulation of the present invention has the following effects.

(1) When manufacturing polyurethane foam that functions as a sound absorbing material in dash inner insulation, it is possible to improve the permeability by changing the cell structure of the foamed polyurethane material by adding carbon nanotubes (CNT) Thereby maximizing the sound absorbing performance compared to the weight increase of the polyurethane foam.

(2) In particular, in the manufacturing process, since only carbon nanotubes are added in the process of manufacturing a polyurethane foam used as a conventional sound absorbing material, the increase in manufacturing cost can be minimized while minimizing the process addition.

(3) By changing the internal structure of the polyurethane foam with the added carbon nanotubes, it is possible to improve the sound absorption performance in all frequencies while maintaining the advantage of light weight of the polyurethane foam material compared to other engine room sound absorption materials .

(4) Therefore, it is possible to maximize the performance of NVH (Noise, Vibration, Harshness) while minimizing cost increase by adding a very small amount of carbon nanotubes, thereby greatly improving the indoor quietness of the automobile.

(5) It is possible to provide a dash inner insulation which can improve the NVH performance while improving the fuel consumption while minimizing the weight increase of the sound absorbing material.

1 is a side view schematically showing a vehicle for showing a mounting position of dash inner insulation.
2 is a cross-sectional view showing a configuration of a dash inner insulation according to the present invention.
3 is a flow chart showing a method for producing a polyurethane foam according to the present invention.
Fig. 4 is an enlarged photograph of the surface of a polyurethane foam by a scanning electron microscope, wherein (a) is an enlarged view of a conventional polyurethane foam, and (b) is a view of a polyurethane foam according to the present invention Closeup.
FIG. 5 is a graph showing data on sound absorption performance of dash inner insulation manufactured according to the content of carbon nanotubes (CNTs) according to the present invention.
FIG. 6 is a graph showing data on sound absorption performance of dash inner insulation made of a polyurethane foam containing carbon nanotubes (CNT) according to the present invention and a comparative example made of a polyurethane foam containing no carbon nanotubes For the graph.
7 is a cross-sectional view of another embodiment showing the construction of a dash inner insulation having another configuration based on a polyurethane foam containing carbon nanotubes according to the present invention.
FIG. 8 is a graph showing the results of the comparison between the comparative example of the dash inner insulation in which the foamed polyurethane foam is not added in the actual vehicle state and the dash inner insulation in which the foamed polyurethane foam d with the carbon nanotubes are applied, In order to show the result of the test of the transmission noise of the test piece.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should properly define the concept of the term to describe its invention in the best possible way The present invention should be construed in accordance with the spirit and scope of the present invention.

Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Thus, various equivalents And variations may be present.

<Dash Inner Insulation of  Configuration>

1 to 8, a dash inner insulation I for an automobile according to the present invention is mounted on a dash panel D for distinguishing between an engine room and an interior, 2, the cell structure of the polyurethane foam is changed by adding carbon nanotubes to the polyurethane foam 100, particularly when the foam is molded into a sheet or a block form so that the weight of the polyurethane foam It is possible to improve the absorption / sound effect in the entire frequency band while minimizing the increase in the frequency band, and to minimize the weight loss, thereby improving the fuel efficiency of the vehicle.

Hereinafter, this configuration will be described in more detail.

1. Manufacturing method of polyurethane foam

3 and 4, the polyurethane foam 100 according to the present invention is prepared in three steps as in a conventional method for foaming and molding a polyurethane foam, in which carbon nanotubes (CNT) are added as a raw material It is. The following is a more detailed description of each step.

The first step S10 is a step of mixing and stirring a polyol, an isocyanate and a carbon nanotube as shown in Fig. At this time, the weight ratio of isocyanate to isocyanate is 40 to 60 and the weight ratio of carbon nanotubes is 0.1 to 7.25, based on 100 weight of polyol.

Here, the polyol, isocyanate and carbon nanotube to be mixed and stirred will be described in more detail as follows.

The polyol is a component which becomes a base material of a polyurethane foam, and is composed of constituent components and weight as shown in Table 1 below. Here, this component is the same as the polyol used in producing the conventional polyurethane foam.

Constituent

Weight ratio
Optimum weight
Polymer PPG

45.0 to 50.0
48
Low molecular PPG

26.0 to 32.0
29
Cell Opener

2.0 to 4.0
3
Chain Extender

3.0 to 5.0
4
Flame-retardant

5.0 to 7.0
6
Silicon Surfactant

1.2 to 1.8
1.5
Amine catalyst

0.8 to 1.2
One
water

6.0 to 9.0
7.5
1) "Weight ratio" refers to the weight ratio constituting each component.

2) "Optimum weight" represents the weight ratio at which the optimum absorbency of the polyurethane foam according to the present invention can be obtained from these weights.

It is preferable to use MDI to obtain a soft polyurethane foam. The ratio of the isocyanate is mixed at a weight ratio of 40 to 60 based on the polyol 100 as described above. Of these, modified MDI having an NCO content of 32.1 wt% is preferably used. Therefore, the weight ratio of isocyanate is not high, so that a flexible polyurethane foam can be produced.

 In addition to the components used in the conventional polyurethane foam manufacturing, it is desirable to minimize the additional content of the carbon nanotubes to be added and to maximize the sound absorption performance by modifying the cellular structure of the polyurethane foam as described later.

In a preferred embodiment of the present invention, the carbon nanotube is a single carbon nanotube having a diameter of 10 to 50 nm, a volume density of 0.02 to 1.50 g / ml, a purity of 85 to 90% and a crystallinity (I _G / I _D ) of 0.7 to 1.1 Wall or a multi-wall structure may be used. Such carbon nanotubes may be prepared in the form of powders or may be added in the form of powder granules.

These polyols, isocyanates and carbon nanotubes are agitated twice as shown in Fig. Here, since the weight ratio is described above, the description of the weight ratio is omitted here.

The first stirring step (S11) is a step of adding carbon nanotubes to the isocyanate stock solution and stirring the mixture. The stirring time is 25 to 35 seconds, preferably 30 seconds. The second stirring step S12 is a step of adding the stock solution, which has been stirred in the step 1-1, to the polyol stock solution, followed by stirring for 6 to 10 seconds, preferably 8 seconds.

The agitation step for forming the substantially foamable polyurethane foam is completed by this two-step stirring.

In the second step S20, as shown in Fig. 3, the solution stirred in the first step S10 is injected into a mold for foaming and foam molding is performed. At this time, the foaming molding is performed in the foaming mold, and the foaming mold can be variously manufactured in consideration of the size and shape of the polyurethane foam.

That is, the foaming mold at this time may be formed into the size and shape of the polyurethane foam to be the base material of the dash inner insulation, and foam molding may be performed on the polyurethane foam one sheet at a time in one foaming mold. Alternatively, A mold for foaming can be manufactured so that the foam can be foam-molded into a block shape, and the block can be sliced into a sheet shape in accordance with the size of the insulation of the engine.

The third step (S30) is a step of demolding the polyurethane foam in the foam mold as shown in Fig. This demolding is performed by a conventional technique, and a detailed description thereof will be omitted here.

Meanwhile, in a preferred embodiment of the present invention, as shown in FIG. 3, a fourth step (S40) of foaming and molding the polyurethane foam in the foaming mold may be further performed. This is for the purpose of enabling the inside of the polyurethane foam to be cooled sufficiently when the polyurethane foam is foam-molded as described above.

At this time, the aging period may vary depending on the size and volume of the polyurethane foam, but in the preferred embodiment of the present invention, the aging period is preferably 3 days.

The polyurethane foam according to the present invention having the above-described structure, as compared with the conventional enlarged photograph (see Fig. 4 (a)) without the addition of carbon nanotubes as shown in Fig. 4 (b) It is possible to confirm that the cell open rate is increased while maintaining the uniform cell structure. This improves the damping function of the polyurethane foam by alleviating the hardness of the polyurethane foam. As a result, the NVH (Noise, Vibration, Harshness) performance is improved remarkably in the entire frequency band. The performance of NVH is described in the graphs tested in the actual state of the dash inner insulation.

Here, the polyurethane foam has a cell structure similar to that of the rigid polyurethane foam, but in the case of the rigid polyurethane foam, the cell structure is closed to have heat insulation and cold storage characteristics, whereas the soft polyurethane foam according to the present invention has a cell structure As shown in FIG. 4, a part of the network structure is opened. Therefore, the polyurethane foam according to the present invention has an effect of canceling out the sound waves which cause noise to the inside of the cell structure, so that the NVH effect is excellent. However, when the cell structure is entirely open, the polyurethane foam is not transmitted through the polyurethane foam and the noise reduction effect can not be obtained.

Accordingly, in the present invention, the open rate of the cell structure is adjusted so that the noise reduction can be performed according to a specific frequency band that matches the required property at the place where the dash inner insulation is mounted through the open rate adjustment of the cell structure. This adjustment is based on the structure of the undiluted solution such as polyol and the composition of other additives. In the present invention, by adding such additives, particularly carbon nanotubes, the open rate of the cell structure can be adjusted to the desired noise frequency band.

4 is an enlarged view of the surface of a foamed polyurethane foam by a scanning electron microscope. In the cell structure, the cell of the polyurethane foam according to the present invention (FIG. 4 (b) It can be seen that there is a closed form of this conventional polyurethane foam cell (Fig. 4 (a)). The open resistance of the cell structure was changed by the change of the cell structure, and the flow resistance was measured by Flow Resistivity Measurement. As a result, compared with the foamed polyurethane foam applied carbon nanotube, The resistance value was low. This is because the foamed polyurethane foam to which the carbon nanotubes are applied has improved air permeability, and the sound absorption performance is greatly improved due to the homogenization of the cell structure and the increase of the ventilation effect.

Here, the results of inductive resistance measurement for air permeability measurement are shown in [Table 2] below.

division

Measured value (mks ravl / m)
Comparative Example

539518
Example

321599
1) The comparative example is a polyurethane foam containing no carbon nanotubes (CNT).

2) An example is a polyurethane foam containing carbon nanotubes (CNTs).

In the preferred embodiment of the present invention, the polyurethane foam sheet prepared as described above is generally known to have a better sound absorbing effect as the density of the sound absorbing material is higher. However, the density is 50 to 130 kg / m &lt; 3 & It is desirable to further improve the performance.

2. Sound absorption performance test by carbon nanotube content

In preparing the polyurethane foam according to the present invention, the carbon nanotubes (CNTs) are added in a ratio of 0.1 to 7.25 parts by weight based on 100 parts by weight of the polyol used for preparing the polyurethane foam. Hereinafter, the sound absorption performance test results of polyurethane foam obtained by mixing carbon nanotubes at different ratios in Examples 1 to 3 will be described.

5, Examples 1 to 3 are dash inner insulation made of flexible polyurethane foam to which carbon nanotube is added. In Example 1, the CNT content was 0.1 wt% based on the total weight of the polyurethane foam, the CNT content was 0.3 wt% based on the total weight of the polyurethane foam in Example 2, the total weight of the polyurethane foam in Example 3 The CNT content is 0.5% by weight. The density of each of Examples 1 to 3 is 100 kg / m3.

In the case of Examples 1 to 3, as shown in FIG. 5 showing the sound absorption performance according to the content of CNT, it can be seen that the greater the content of CNT, the better the sound absorption rate in the entire frequency band. 5, the horizontal axis represents the frequency and the vertical axis represents the sound absorption rate.

3. Comparison of sound absorption performance with and without addition of carbon nanotubes

According to the present invention, the sound absorption performance of the dash inner insulation made of a polyurethane foam with carbon nanotubes (CNT) added and the dash inner insulation made of a polyurethane foam not containing carbon nanotubes The results of the test are shown in FIG. 6 below.

In FIG. 6, the abscissa represents the frequency and the ordinate represents the sound absorption ratio. The density of the polyurethane foam used in the examples and the comparative examples is 100 kg / m 3, respectively. Examples include 0.3 wt% of carbon nanotubes (CNT) will be.

As shown in FIG. 6, it can be seen that the sound absorption performance of the embodiment shown by the red line is high in the entire frequency band. Particularly, the higher the frequency band, the higher the sound absorption ratio.

Particularly, in the embodiment of the present invention, the content of carbon nanotubes (CNT) is 0.3% by weight, and the increase rate of the total weight of the dash inner insulation is small, but the sound absorption rate is excellent over the entire frequency band.

For reference, the embodiment used for the sound absorption performance according to the presence or absence of the carbon nanotubes is the same composition as that of the embodiment 2 according to the content of the carbon nanotubes.

4. Of insulation  Other Example

Another embodiment according to the present invention differs from the first to third embodiments in accordance with the content of the carbon nanotubes described above, in which a polyurethane foam (100) containing carbon nanotubes (CNT) · The sound insulation layer is further added.

This configuration will be described in more detail as follows.

In Example 4, a sound insulating layer 200 is formed on a polyurethane foam 100 containing carbon nanotubes (CNT) as a base material to have a two-layer structure as shown in Fig. 9 (a).

In the preferred embodiment of the present invention, the sound insulating layer 200 that can be used in the fourth embodiment includes EVA (Ethylene Vinyl Acetate), TPE (Thermo Plastic Elastomer), PET (Poly Ethylene Terephthalate), natural rubber, NDR RUBBER).

Accordingly, the dash inner insulation according to the fourth embodiment can enhance the sound absorption effect and the sound insulation effect at the same time through the polyurethane foam 100 containing the carbon nanotube according to the present invention.

In Example 5, as shown in Fig. 9 (b), a sound absorbing layer 300 is formed on a polyurethane foam 100 containing carbon nanotubes (CNT) as a base material, and the base material is formed into a two-layer structure.

In the preferred embodiment of the present invention, the sound-absorbing layer 300 that can be used in Embodiment 5 includes PET (Poly Ethylene Terephthalate) felt, PP (Polypropylene) felt, Nonwoven, Glass Wool, Resin) felt.

As the nonwoven fabric, for example, general nonwoven fabric, reinforced nonwoven fabric, water repellent nonwoven fabric, reinforced / foamed nonwoven fabric and the like can be used. This is because the required physical properties of the dash inner insulation are different for each company, so that the dash inner insulation can be selected and used in consideration of the strength of the dash inner insulation. The reinforced / water repellent nonwoven fabric is made to improve the resistance to humidity by adding a water repellent agent to the surface by increasing the amount of LMF (Low Melting Fiber) than the conventional nonwoven fabric.

In the dash inner insulation according to the fifth embodiment, the sound absorbing effect is enhanced through the sound absorbing layer 300 having different sound absorbing characteristics while the sound absorbing effect is enhanced through the polyurethane foam 100 containing the carbon nanotube according to the present invention. It is possible to further improve.

In Example 6, as shown in Fig. 9 (c), a sound absorbing layer 300 and a sound insulating layer 200 are sequentially stacked on a polyurethane foam 100 containing carbon nanotubes (CNT) Structure.

Thus, sound absorption and sound insulation are effectively performed while passing through the sound absorption characteristic and the sound insulation characteristic which are different in noise.

In Example 7, a sound absorbing layer 300 and a sound insulating layer 200 are stacked on both sides of a polyurethane foam 100 containing carbon nanotubes (CNT) as shown in Fig. 9 (d) Layer structure.

Thus, in the seventh embodiment, as in the sixth embodiment, sound absorption and sound insulation are effected while passing through the sound insulation characteristic and the sound absorption characteristic which are different from each other in turn.

Accordingly, dash inner insulation of various structures can be manufactured from a polyurethane foam having various sound absorption performances according to the content of carbon nanotubes (CNTs) manufactured according to the present invention.

5. Actual vehicle  Transmission noise test

FIG. 8 is a graph showing the relationship between the permeation noise (%) and the permeation noise (%) with respect to the comparative example of the dash inner insulation using foamed polyurethane foam not containing carbon nanotubes in the actual vehicle state and the dash inner insulation using foamed polyurethane foam with carbon nanotubes, AI). In the graph, the abscissa represents the speed (rpm) and the ordinate represents the transmission noise (% AI), in which (a) and (b) show the results measured at the driver's seat and the passenger's seat respectively.

In this example, a polyurethane foam having a density of 100 kg / m 3 and a carbon nanotube (CNT) content of 0.3 wt% is used as a substrate, and PET (Poly Ethylene Terephthalate) and TPT Plastic Elastomer). The comparative example has the same structure but the polyurethane foam does not contain carbon nanotubes.

As shown in the graph of FIG. 8, it can be seen that the case of the embodiment (red line) shows a better transmission noise effect than the comparative example (black line) in almost all the speed sections, The average improvement was 4.8%, and the passenger seat improved 2.6% as shown in FIG. 8 (b).

Accordingly, the present invention can improve the absorption sound effect in the entire frequency band while minimizing the increase in the total weight of the polyurethane foam by manufacturing the dash inner insulation using the polyurethane foam containing the carbon nanotube having such excellent properties as the sound absorbing material , And the fuel consumption can be improved by reducing the weight.

100: polyurethane foam
200: Sound insulating layer
300: sound-absorbing layer

Claims (10)

(100) in which polyisocyanate (Isocyanate) having a weight ratio of 40 to 60 and carbon nanotubes having a weight ratio of 0.1 to 7.25 are mixed and stirred with respect to 100 weight of the polyol, and then foamed Automotive dash inner insulation.
The method according to claim 1,
Adding carbon nanotubes to the isocyanate / undiluted solution, stirring the mixture for 25 to 35 seconds, adding the solution to the polyol stock solution, and further stirring for 6 to 10 seconds to foam.
3. The method according to claim 1 or 2,
The polyol has a weight ratio of
Polymer PPG: 45.0 ~ 50.0
Low molecular weight PPG: 26.0 ~ 32.0
Cell Opener 2.0 ~ 4.0
Chain Extender: 3.0 to 5.0
Flame-retardant: 5.0 to 7.0
Silicon Surfactant: 1.2 to 1.8
Amine catalyst: 0.8-1.2
Water: 6.0 to 9.0
Wherein the dash inner insulation is made of a resin.
The method according to claim 1,
Wherein the carbon nanotube is a single wall or multiple wall having a diameter of 10 to 50 nm, a bulk density of 0.02 to 1.50 g / ml, a purity of 85 to 90% and a crystallinity (I _G / I _D ) of 0.7 to 1.1, Wherein the insulation is formed in a granular form.
The method according to claim 1,
Wherein the polyurethane foam (100) has a density of 50 to 130 kg / m &lt; 3 &gt;.
6. The method according to any one of claims 1 to 5,
Wherein the dash inner insulation has at least one of a sound insulating layer (200) and a sound absorbing layer (300) on at least one side of both sides.
The method according to claim 6,
The sound insulating layer 200 is made of at least one of ethylene vinyl acetate (EVA), thermo plastic elastomer (TPE), poly ethylene terephthalate (PET), natural rubber, and NDR (NOISE DAMPING RUBBER) Insulation.
8. The method of claim 7,
The sound absorbing layer (300) is made of at least one of PET (Poly Ethylene Terephthalate) felt, PP (Polypropylene) felt, Nonwoven, Glass Wool and Resin felt. Insulation.
9. The method of claim 8,
Wherein the nonwoven fabric is a general nonwoven fabric, a reinforced nonwoven fabric, a water repellent nonwoven fabric, or a reinforced / foamed nonwoven fabric.
10. The method of claim 9,
Wherein the nonwoven fabric is a general nonwoven fabric, a reinforced nonwoven fabric, a water repellent nonwoven fabric, or a reinforced / foamed nonwoven fabric.

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