JP3129098B2 - Sound absorbing material for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing material used for a vehicle having a noise source, and more particularly to a sound absorbing material which is provided on a soundproof wall or the like in a laminated manner and exhibits sound absorbing properties.

[0002]

2. Description of the Related Art An engine and a drive system mounted on a vehicle or the like generate noise when driven. In order to prevent this noise from causing discomfort to the occupants, the engine hood,
As a noise countermeasure, a sound absorbing material is often provided in a laminated manner on the wall surface of a wall material such as a dash panel, a noise cover, and a cab floor. For example, Japanese Patent Publication No. 5-718 discloses a sound absorbing material including a fiber layer made of inorganic or organic long fibers and a hard resin layer integrally formed on one side of the fiber layer by pressure firing. Is done. The sound-absorbing material has a vibration-proof fiber layer,
The sound insulation is improved, the hard resin layer has sufficient rigidity, and is excellent in heat insulation.

Further, Japanese Patent Laid-Open No. 2-41476 discloses that
Opening and laminating the nonwoven fabric material, applying needle punching while stretching, processing into a plate-shaped material, immersing this plate-shaped material in an impregnation tank filled with a binder and an oil repellent selected from silicon and fluorine A food insulator manufactured by removing excess binder and oil repellent by a pair and volatilizing a solvent is disclosed. The insulator can ensure oil repellency and can attain almost the same sound absorption performance after the volatile oil treatment as before the treatment. FIG. 4 shows the sound absorbing characteristics of various existing sound absorbing materials. Here, in FIG.
The diagrams indicated by b, c, d, and e show the sound absorbing properties of glass wool, PP (polypropylene) nonwoven fabric, acrylic-impregnated urethane, soft foamed urethane, and 30-fold foamed PP (polypropylene), respectively, as the thickness increases. It is clear that the sound absorption is enhanced.

[0005] Further, the diagram indicated by reference numerals f, g, and h in FIG. 5 shows that a nonwoven fabric made of PET (polyethylene terephthalate) fiber has a main fiber diameter of 1.5 denier (1
2.4 μ), 3 deniers (17.5 μ), and 14 deniers (38.0 μ) show the respective sound absorbing characteristics. FIG. 6 is a diagram indicated by reference numerals i, j, and k is a PET (polyethylene terephthalate) fiber. , PP (polypropylene) nonwoven fabric and glass wool have respective sound absorbing properties. From these, it is clear that the sound absorbing effect increases as the bulk density kg / m ³ increases. However, in the case of PET (polyethylene terephthalate) fiber, when the main fiber diameter is 15 μm or less,
On the contrary, the sound absorbing effect decreases.

By the way, as described above, glass wool, PE
A sound absorbing material such as a nonwoven fabric made of T (polyethylene terephthalate) fiber is provided in an engine room,
If the water and oil scatter and receive dirt, the water and oil permeate the sound-absorbing material, and if they become dirty, the sound absorbing performance shown in FIG. Problem easily occurs. Therefore, as described above, a hood insulator impregnated with an oil repellent is used as the sound absorbing material provided in the engine room, as shown in JP-A-2-41476, or as shown in FIG. Sound absorbing material is adopted.

In FIG. 8, a sound absorbing material 3 is laminated on an entire inner surface 2, which is a wall facing an engine room, of a sound absorbing cover 1 such as an engine hood, a dash panel, and a cab floor made of sheet metal or resin. . This sound absorbing material 3 is made of glass wool 4 having a predetermined thickness, a PE film (polyethylene film) 5 wrapping the front and back surfaces thereof, a glass cloth 6 wrapping the outside thereof, and an aluminum foil 7 adhered to the glass cloth 6 on the surface facing the engine room. It is composed of Here, in particular, water and oil from which the aluminum foil 7 is scattered are mixed with the glass cloth 6.
Infiltration of the sound-absorbing material due to impregnation with water and oil can be prevented.

[0007]

However, the sound absorbing characteristics of the sound absorbing material mainly composed of glass wool show the characteristics indicated by the symbol a in FIG. As shown by the symbol A in FIG. This is presumably because the noise in the engine room is reflected on the surface of the aluminum foil 7 and reaches a sound absorbing material such as glass wool to reduce the rate of sound absorption.

On the other hand, as shown in Japanese Patent Application Laid-Open No. 2-41476, when a hood insulator impregnated with an oil repellent selected from a silicon type and a fluorine type is used, the oil repellent is the main material of the sound absorbing material. There is a drawback that the sound absorbing material is apt to deteriorate in sound absorbing properties due to being attached to the entirety, and unnecessary costs are increased. The purpose of the invention of claim 1 to claim 3 of the present invention, provides the sound absorption sound absorbing material amenable to water repellent oil repellent treatment without causing a reduction in conjunction with selected as the fiber diameter and excellent sound absorbing characteristics Is to do.

[0009]

In order to achieve the above-mentioned object, the invention according to claim 1 is directed to a bulk density of 0.05 g / cm < ³ > formed of resin fibers having a fiber diameter of 15 to 25 [mu] m.
The surface of a nonwoven fabric of 0.2 g / cm ³ is subjected to a water / oil repellent treatment. As another aspect of the first aspect,
The fiber may be made of polyethylene terephthalate. According to a second aspect of the first aspect of the present invention, the fiber may be made of polypropylene. According to a second aspect of the present invention, in the sound absorbing material for a vehicle according to the first aspect, the water / oil repellent treatment heats and melts the surface of the nonwoven fabric to form a resin film.

In a third aspect of the present invention, the water repellent and
The oil repellent treatment may be a coating of a liquid water repellent / oil repellent substance on the surface of the nonwoven fabric. According to a third aspect of the present invention, in the sound absorbing material for a vehicle according to the first aspect, the water repellent / oil repellent treatment is performed on the surface of the nonwoven fabric with the same water repellent material as that of the fiber.
It is characterized by being a coating of an oil-repellent layer.

[0011]

According to a first aspect of the present invention, a bulk density of 0.05 g / cm ³ to 0.1 μm is formed by resin fibers having a fiber diameter of 15 μm to 25 μm.
2 g / cm ³ non-woven fabric , ie fiber diameter and bulk density
Considering that the fiber diameter is relatively large and the bulk density
To maintain an appropriate thickness.
As a result, a nonwoven fabric with excellent sound absorption characteristics is obtained while suppressing weight increase.
Water- and oil-repellent treatment on the surface of the non-woven fabric.
To prevent the sound absorption characteristics from deteriorating due to the intrusion of water or oil.
I can . As another aspect of the first aspect, in particular, when a fiber made of polyethylene terephthalate is used, the sound absorbing property of the polyethylene terephthalate is obtained. According to a second aspect of the first aspect of the present invention, in particular, when polypropylene fibers are used, the sound absorbing characteristics of the polypropylene are obtained.

According to a second aspect , in the sound absorbing material for a vehicle according to the first aspect, since the resin film is formed by heating and melting the surface of the nonwoven fabric, the sound absorbing property is excellent while suppressing an increase in weight.
Using nonwoven, a resin film of that can be used as a water-repellent oil-repellent treatment layer, it is possible to prevent deterioration of sound absorption characteristics. According to a third aspect of the present invention, the water-repellent / oil-repellent layer is formed by coating a liquid water-repellent / oil-repellent substance on the surface of the nonwoven fabric, so that the surface of the nonwoven fabric exhibits water / oil repellency. Become.
According to a third aspect of the present invention, in the sound absorbing material for a vehicle according to the first aspect, in particular, a nonwoven fabric having excellent sound absorbing properties while suppressing weight increase.
Since the surface of the fabric provided a coating of repellent layer of the fibers the same material, and more water and oil repellency layer the skin material to form
It is possible to prevent a decrease in sound absorption characteristics .

[0013]

FIG. 1 shows a sound absorbing material according to the present invention. The sound absorbing material 10 is provided in a laminated manner on an inner wall surface 12 of a soundproof cover 11 surrounding an engine room of an engine (not shown). Here, the soundproof cover 11 is made of sheet metal or resin, and the sound absorbing material 10 is formed on the inner wall surface 12 of the inner plate 111.
Is affixed. The sound absorbing material 10 has a nonwoven fabric 13 and a water-repellent / water repellent layer provided on the engine room side surface of the nonwoven fabric.
And an oil-repellent layer 14. The nonwoven fabric 13 is made of polyester fiber, for example, PET (polyethylene terephthalate) fiber, and the thickness of the nonwoven fabric 13 increases as shown in FIG. Then, an appropriate thickness T is determined.

It is clear from FIGS. 5 and 6 that the higher the bulk density of the PET non-woven fabric 13 is, the better the sound absorption characteristics are. In this case, the main fiber diameter is 17.5 μm.
A bulk density of 0.1 g / cm ³ was selected and adopted. The water-repellent / oil-repellent treatment layer 14 has a property of excluding water / oil directed toward the inside of the nonwoven fabric 13.
The surface layer of the nonwoven fabric 13 made of PET (polyethylene terephthalate) fiber is subjected to a thermal treatment to form a resin film layer. In order to heat and melt the nonwoven fabric 13 to form the water-repellent / oil-repellent treatment layer 14 composed of a resin film layer, an appropriate heating means H is used.

For example, as shown in FIG. 7, the heating means H is provided with a mold 15 capable of shaping the outer shape of the sound absorbing material 10, a heater 16 is provided below the mold 15,
5 is maintained at a temperature at which the PET fiber can be melted. Further, a PET (polyethylene terephthalate) fiber 1 preformed under pressure into a predetermined shape for the nonwoven fabric 13
The 3 'is placed in the mold 15 and is heated and held for a predetermined time and then cooled and held. As a result, the PET fiber 1
In 3 ′, only a predetermined thickness portion of the surface facing the mold 15 is heated and melted to form a water-repellent / oil-repellent treatment layer 14 which is a resin film layer. The formation of the water-repellent / oil-repellent treatment layer 14 includes
The water-repellent / oil-repellent treatment layer 14 may be formed on the surface of the PET fiber 13 'by using other heating and melting means, for example, a burner or a trowel (heating).

When such a sound absorbing material 10 shown in FIG. 1 is disposed on the inner wall surface 12 of the soundproof cover 11, the water and oil scattered from the engine room side are repelled by the PET fiber formed by thermal treatment. The infiltration into the nonwoven fabric 13 is prevented by the water / oil repellent treatment layer 14. For this reason, the sound absorbing material 10 of FIG. 1 does not deteriorate in sound absorbing properties due to impregnation of water and oil, and has a sound absorbing property of PET fiber, that is, a main fiber diameter of 17.5 μm and a bulk density of 0.1 g. / Cm ³ ,
A sound absorbing effect of about 4.8 dB (A) can always be ensured. . In the first embodiment, the nonwoven fabric 13 is a PET fiber, but a PP (polypropylene) fiber having a lower melting point may be used. In this case, the water-repellent and oil-repellent resin-fused resin film layer is used. Manufacturing of the processing layer 14 becomes easier.

Although the sound absorbing material 10 of the first embodiment uses PET (polyethylene terephthalate) fiber as the nonwoven fabric 13, the sound absorbing material 10a of the second embodiment shown in FIG. 2 may be used instead. . The sound absorbing material 10a according to the second embodiment includes a nonwoven fabric 13a and a water-repellent / oil-repellent treatment layer 14a provided on the engine room side surface of the nonwoven fabric in a laminated manner.
It is composed of The nonwoven fabric 13a is formed to an appropriate thickness T using PP (polypropylene) fiber. This P
It is clear from the sound absorption characteristic diagram of FIG. 6 that the higher the bulk density of the P fiber is, the better the sound absorption characteristic is. Here, the main fiber diameter is 20.0 μm and the bulk density is 0.15 g / cm ³ . Selected and adopted.

The water-repellent / oil-repellent treatment layer 14a has a property of excluding water / oil directed toward the inside of the nonwoven fabric 13a. In this case, the nonwoven fabric 13 made of PP (polypropylene) fiber is used.
It is formed by applying a chemical treatment to the surface portion t of a, that is, by applying a silicon-based or fluorine-based water / oil repellent. In the application of the water / oil repellent to the surface of the nonwoven fabric 13a, a binder is mixed with a silicon-based or fluorine-based water / oil repellent, and spray-coating is performed. Layer 14a can be formed.

When the sound absorbing material 10a shown in FIG. 2 is disposed on the inner wall surface 12 of the soundproof cover 11, the water and oil scattered from the engine room side are silicon-based and fluorine-based water and water repellents. The infiltration into the nonwoven fabric 13a is prevented by the water-repellent / oil-repellent treatment layer 14a to which an oil agent is applied, that is, formed by chemical treatment. For this reason, the sound absorbing material 10 of FIG.
a is a sound absorbing property of the PP fiber without impairment by water and oil impregnation, ie, the main fiber diameter is 20.
If the bulk density is 0 μm and the bulk density is 0.15 g / cm ³ , a sound absorbing effect of about 5.0 dB (A) can always be ensured. The sound absorbing material 10 of the first embodiment is a water repellent / oil repellent layer 1
4. Water repellency formed by thermal treatment of PET fiber
Although the oil-repellent treatment layer 14 prevents penetration into the nonwoven fabric 13, the sound absorbing material 10b according to the third embodiment shown in FIG. 3 may be used instead. The sound absorbing material 10b according to the third embodiment is made of a nonwoven fabric 13b of PET fiber and a water repellent / water repellent layer provided on the engine room side surface of the nonwoven fabric.
And an oil-repellent layer 14b.

The non-woven fabric 13b is made of PET fiber, has an appropriate thickness T, and the non-woven fabric 13b has a main fiber diameter of 17.5 μm and a bulk density of 0.15 g / cm ³ . Was adopted. The water-repellent / oil-repellent treatment layer 14b is a skin material having a property of eliminating water and oil heading toward the inside of the nonwoven fabric 13b, and is formed as a skin material covering the entire surface of the nonwoven fabric 13b. The water-repellent / oil-repellent treatment layer 14 in the form of a skin material
b is made of a sheet made of the same PET fiber as the nonwoven fabric 13b as a material, and a silicon-based or fluorine-based water / oil repellent impregnated in the sheet.

When such a sound absorbing material 10b shown in FIG. 3 is disposed on the inner wall surface 12 of the soundproof cover 11, the water and oil scattered from the engine room side are silicon-based and fluorine-based water and water repellents. The water-repellent / oil-repellent treatment layer 14b, which is a skin material impregnated with an oil agent, prevents penetration into the nonwoven fabric 13b. For this reason, the sound absorbing material 10b of FIG. 3 does not decrease in sound absorbing property due to impregnation of water and oil, and the sound absorbing property of the PET fiber, that is, the main fiber diameter here is 17.5 μm.
When the bulk density is 0.15 g / cm ³ , about 5.2
A sound absorbing effect of about dB (A) can always be ensured. The water-repellent / oil-repellent layer 1 covering the nonwoven fabric 13b
The skin material as 4b may be in the form of a sheet as described above,
It may be a film or foil that has been subjected to water / oil repellency treatment and processed into a shape that does not impair the sound absorption of the base material, but in any case, a material similar to the nonwoven fabric 13b is preferable.

[0022]

As described above, the invention of claim 1 uses a nonwoven fabric having a bulk density of 0.05 g / cm ^{3 to} 0.2 g / cm ³ formed of resin fibers having a fiber diameter of 15 μm to 25 μm . That is, by considering the fiber diameter and bulk density,
Use a fiber with a relatively large diameter and a high bulk density.
As a result, while maintaining an appropriate thickness, while suppressing weight increase
A nonwoven fabric with excellent sound absorption characteristics can be obtained, and the
Water- and oil-repellent treatment on the surface reduces sound absorption
It is suitable for the cover around the engine, for example.
A sound absorbing material for vehicles can be provided. Another aspect of claim 1,
Secondly, particularly when fibers made of polyethylene terephthalate or polypropylene are used, accurate sound absorption characteristics can be obtained. The invention of claim 2 is particularly advantageous for weight
By heating and melting the surface of the non-woven fabric with excellent sound absorption characteristics while suppressing the increase, forming a resin film and using it as a water- and oil-repellent treatment layer, it is possible to prevent the sound absorption characteristics from deteriorating.
In addition, recyclability can be improved and cost can be reduced.

According to a third aspect of the present invention, in particular, the surface of the non-woven fabric is coated with a liquid water-repellent / oil-repellent substance to provide a water-repellent / oil-repellent material.
When the oil-repellent layer is formed, the number of sound absorbing materials is not particularly increased, the cost can be reduced, and the weight can be easily reduced. The invention according to claim 3 is particularly advantageous in suppressing suction while suppressing weight increase.
Shape Runode, the skin material to the sound characteristics superior surface of the nonwoven fabric is provided a coating of repellent layer of fibers of the same material of the same nonwoven fabric
The formed water- and oil-repellent layer can prevent the sound-absorbing properties from deteriorating.
In addition , recyclability can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a sound absorbing material as one embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a sound absorbing material as another embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a sound absorbing material as another embodiment of the present invention.

FIG. 4 is a diagram showing thicknesses of various sound absorbing materials and sound absorbing characteristics.

FIG. 5 is a diagram showing the bulk density and sound absorption characteristics of a PET nonwoven fabric.

FIG. 6 is a diagram showing the bulk density and sound absorbing properties of nonwoven fabrics of PET and PP and glass wool.

FIG. 7 is a schematic structural view of a heating means for forming a water / oil repellent treatment layer on the nonwoven fabric of FIG. 1;

FIG. 8 is a cross-sectional view of a main part in a state before sticking of a current sound absorbing material.

[Explanation of symbols]

 Reference Signs List 10 sound absorbing material 10a sound absorbing material 10b sound absorbing material 11 soundproof cover 12 inner wall surface 13 nonwoven fabric 13a nonwoven fabric 13b nonwoven fabric 14 water / oil repellent treatment layer 14a water / oil repellent treatment layer 14b water / oil repellent treatment layer

Claims (3)

(57) [Claims] 1. A bulk density of 0.05 g / cm ^{3 to} 0.2 g / c formed of resin fibers having a fiber diameter of 15 μm to 25 μm.
The vehicle sound absorbing material, characterized in that subjected to water-repellent oil repellent treatment on the surface of the m ³ of the nonwoven fabric. 2. The water- and oil-repellent treatment heats and melts the surface of the nonwoven fabric to form a resin film.
The sound absorbing material for a vehicle according to claim 1 . 3. The sound-absorbing material for a vehicle according to claim 1, wherein the water-repellent / oil-repellent treatment is a coating of the surface of the nonwoven fabric with a water-repellent / oil-repellent layer of the same material as the fibers.