JP2002215169A - Acoustic material for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acoustic material for vehicles which is applied to molded ceilings, etc., and is capable of effectively absorbing the noises particularly from a middle frequency region to a high frequency region. SOLUTION: A low-density nonwoven fabric 13 having bulkiness and flexibility is interposed between a base material compounded with glass fibers and PP fibers (resins) and an outer skin 12. The low-density nonwoven fabric 13 makes it possible to expect a porous sound absorption effect when the outer skin 12 has air permeability. When the outer skin 12 is air impermeable, the fabric has a function to attenuate the energy of the membrane vibration of the outer skin 12. Further, when a ventilation stopping film 15 is stuck to the rear surface of the base material 11, the filter effect of the outer skin 12 is eliminated and the pickup of dirt and dust on the surface can be prevented. The absorption of the reflected noise reflected by the ventilation stopping film 15 again by the base material 11 and the low-density nonwoven fabric 13 is made possible and high sound absorption performance is obtained.

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 for a vehicle suitable for a molded ceiling for a vehicle and the like, and more particularly to a sound absorbing material for a vehicle capable of effectively absorbing high-frequency noise in a vehicle cabin.

[0002]

2. Description of the Related Art For example, various sound absorbing materials are installed in the interior of a vehicle. For example, a molded ceiling mounted on the interior surface of a roof panel is, as shown in FIG. A skin 3 is laminated and integrated on the front side of the base material 1 with an adhesive film 2 interposed therebetween, and a back nonwoven fabric 4 for preventing damage due to friction with a panel is attached to the back side of the base material 1. .

As another conventional example, as shown in FIG. 10, a material in which both surfaces of a foamed urethane 1a are laminated in a sandwich shape by a glass mat 1b as a base material 1 is used, and a skin 3 such as a tricot cloth is used. A structure in which the front surface side is laminated and integrated, and the back surface side is provided with a ventilation preventing film 5 and a back surface nonwoven fabric 4, respectively, is used.

Further, as shown in FIG. 11, a skin 3 is laminated on the surface of a non-breathable substrate 1 such as a cardboard or a polyphenylene oxide (hereinafter referred to as PPO) foamed resin sheet.
A structure in which a felt 6 as a sound absorbing material is attached to the back surface side is also used.

[0005]

However, in the structure of the conventional sound absorbing material for a vehicle, for example, when the base material 1 based on the sound absorbing nonwoven fabric shown in FIG. 9 is used, the sound absorbing nonwoven fabric is expensive. Therefore, it is pointed out that the material cost is significantly increased, and that the rigidity of the product is difficult to increase because the base material 1 is a nonwoven fabric, and that it is difficult to cope with modularization of the molded ceiling.

Further, in the case of using the base material 1 shown in FIG. 10 in which both surfaces of the urethane foam 1a are sandwiched by a glass mat 1b in a sandwich shape, since it contains glass, it is disadvantageous in terms of recycling and the weight of the product. There is a problem that it is disadvantageous in terms of mounting workability and the like.

[0007] Further, in the type in which the felts 6 are attached to the back surface of the base material 1, when the non-breathable base material 1 such as a corrugated cardboard or a PPO foam sheet is used, most of the indoor noise is caused by the base material 1. Due to the reflection, even if the felts 6 are attached to the back surface of the base material 1, the effect of improving the sound absorbing property is small, and the man-hour for attaching the felts 6 is added, which leads to an increase in manufacturing cost. was there.

The present invention has been made in view of the above circumstances, and provides an excellent sound absorbing performance to a general base material obtained by adding glass fiber to a synthetic resin such as a polypropylene (hereinafter, referred to as PP) resin. It is an object of the present invention to provide a vehicle sound absorbing material that can be provided.

[0009]

In order to achieve the above object, the invention described in claim 1 of the present application is directed to a method of manufacturing a vehicle according to the present invention, in which a base material attached to the interior side of a vehicle body panel and a skin located on a product surface side are provided. And a low-density nonwoven fabric having bulkiness and flexibility is interposed.

[0010] Here, as the substrate, "glass fiber + P
Materials having air permeability such as “P fiber”, “glass fiber + PP resin”, and “resin felt”, and independent foams such as corrugated cardboard, corrugated cardboard plastic, and PPO resin foam sheet;
Non-breathable materials can also be used. However, when a base material having air permeability is used, a porous sound absorbing performance is obtained, so that the sound absorbing property tends to be improved. Further, when glass fibers are mixed, if the compounding ratio of the glass fibers is increased to 30 parts by weight or more, the surface area of the base component is increased, and the sound absorbing property is improved.

[0011] Next, the basis weight of the low density nonwoven fabric having a bulky and flexible good range of 50~700g / m ^2, preferably 100 to 400 g / m ² is desirable. The low-density nonwoven fabric has a thickness of 1 to 10 mm, preferably 3 to 10 mm.
~ 7 mm is good.

Further, the material of the low-density nonwoven fabric is PE
Synthetic fibers such as T (abbreviation of polyethylene terephthalate, polyester fiber), PP, PE, PA (polyamide resin) are suitable, and natural fibers may be used if they have flexibility. In the case of synthetic fibers, the use of fine fibers having a fiber diameter of 30 denier or less, preferably 6 denier or less, can greatly contribute to sound absorption.

According to the first aspect of the present invention,
As a function of the low-density nonwoven fabric, when the skin has air permeability, it exhibits the porous sound absorbing performance of the low-density nonwoven fabric, and when the skin does not have air permeability, the skin receives sound energy and converts it into vibration This vibration is attenuated by the low-density nonwoven fabric.

Accordingly, the sound absorbing performance of the low-density nonwoven fabric is added to the sound absorbing performance of the base material, so that excellent sound absorbing performance can be obtained.

According to the invention described in claim 2 of the present application, the skin is
It is characterized by being a low weight nonwoven fabric.

Here, the nonwoven fabric having a low basis weight used as the skin is preferably a nonwoven fabric which is colored or printed, and a general nonwoven fabric which is colored or printed is subjected to coloring or printing, and this is applied to the indoor side of the low density nonwoven fabric. Laminating is used as a substitute for the skin. The basis weight of this nonwoven fabric is
In the range of ^{20 to} 200 g / m ² , usually 50 to 100 g / m ²
g / m ² is sufficient.

The invention described in claim 3 of the present application is characterized in that the skin and the low-density nonwoven fabric are colored in the same color.

According to the third aspect of the present invention,
The low-density nonwoven fabric inside the low-density nonwoven fabric may be seen through the low-density nonwoven fabric that functions as the skin, and the weight per unit area of the low-density nonwoven fabric is limited. Thus, the basis weight of the surface nonwoven fabric can be set small.

The invention according to claim 4 of the present application is characterized in that a bulky and flexible low-density nonwoven fabric is laminated as a product skin on the surface of a base material attached to the indoor side of the vehicle body panel. .

When a bulky and flexible low-density nonwoven fabric is used as the skin, the entire low-density nonwoven fabric or only the surface may be colored and replaced with a skin. Print may be used as a coloring method. . This configuration is preferred when a coarse surface appearance is desired.

According to the invention described in claim 4,
The sound-absorbing material has a two-layer structure consisting of a base material and a low-density non-woven fabric bonded to the surface of the base material. The low-density non-woven fabric has sound absorbing performance and a skin function. Can contribute.

The invention described in claim 5 of the present application is characterized in that the base material and the low-density nonwoven fabric are bonded with a gas-permeable adhesive.

Here, the adhesive having air permeability includes:
A spider web-like hot melt, a randomly dispersed resin powder, or the like is conceivable.

According to the fifth aspect of the present invention,
Adhesion by a bonding means having air permeability does not reflect incident sound, so that the sound absorbing property of the base material itself can be effectively brought out.

[0025] The invention described in claim 6 of the present application is characterized in that a ventilating film is attached to the back surface of the substrate.

According to the sixth aspect of the present invention,
If a non-breathable film or a non-breathable film and a back nonwoven fabric are laminated on the back surface to prevent ventilation, the skin does not function as a filter and dust and the like can be reliably prevented from adhering to the skin.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the sound absorbing material for a vehicle according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a front view of a molded ceiling to which the present invention is applied, as viewed from the indoor side, FIG. 2 is a cross-sectional view showing the configuration of a first embodiment of a vehicle sound absorbing material according to the present invention, and FIG. FIG. 4 is a cross-sectional view showing a configuration of a modification of the first embodiment of the vehicle sound absorbing material according to the present invention, FIG. 4 is a cross sectional view showing the configuration of the second embodiment of the vehicle sound absorbing material according to the present invention, and FIG. Sectional drawing which shows the structure of the modification of 2nd Embodiment of the sound absorbing material for vehicles,
FIG. 6 is a sectional view showing a configuration of a third embodiment of the vehicle sound absorbing material according to the present invention, and FIG. 7 is a third view of the vehicle sound absorbing material according to the present invention.
FIG. 8 is an explanatory diagram showing a configuration of a modification of the embodiment, and FIG. 8 is a graph showing a difference in sound absorption coefficient between the present invention and a conventional example.

In FIG. 1, a molded ceiling 10 has an outer shape that covers the interior surface of a roof panel of a vehicle (not shown), and a concave portion 10a for accommodating a sun visor at a front side edge portion, and a room lamp mounting hole 10b at a central portion. It is formed into a gently curved shape having assist grip storage recesses 10c provided on both sides.

In the first embodiment of the vehicle sound absorbing material according to the present invention applied to the molded ceiling 10, as shown in FIG. 2, a skin 12 is bulky and flexible on the surface side of a base material 11 serving as a base. It is composed of a three-layer laminated body integrated via a low-density nonwoven fabric 13 having properties.

The base material 11 comprises 55 parts by weight of glass fiber,
The nonwoven fabric mat containing 45 parts by weight of PP fiber is softened by heating and then cold-pressed into a required shape, and the basis weight is set to about 800 g / m ² .

As an alternative to the substrate 11, glass fiber +
PP resin and resin felt can also be used. In particular, when glass fiber is added, when the blending ratio is 30 parts by weight or more, the surface area in the components of the base material 11 increases, so that the sound absorbing property is reduced. improves.

Although the skin 12 is made of tricot cloth in this embodiment, various cloths and resin sheets such as jersey type and moquette type can be used. Further, cost and weight reduction are taken into consideration. And the epidermis 12
Low-weight nonwoven fabric, a basis weight of 20 to 200 g / m ² , preferably 50 to 100 g / m ² can be used. If the low-weight nonwoven fabric is subjected to coloring or printing, it is lightweight and inexpensive. An epidermis 12 can be provided.

Next, the bulky and flexible low-density nonwoven fabric 13 inserted between the base material 11 and the skin 12 is made of PE
Synthetic fibers such as T, PP, PE, PA, etc., natural fibers can be used if they are flexible, and in the case of synthetic fibers, the fiber diameter should be 30 denier or less, preferably 6 denier or less. It is preferable to use ultrafine fibers when sound absorption performance is considered.

Further, the low-density nonwoven fabric 13 is
In the case where a low-weight nonwoven fabric is used, by applying a coloring process similar in color to the skin 12, the weight per unit area of the low-weight nonwoven fabric can be reduced to the maximum.

Therefore, according to the laminated structure shown in FIG. 2, the noise in the passenger compartment is absorbed by the porous sound absorbing function of the low-density nonwoven fabric 13 through the skin 12 having air permeability.
Further, most of the remaining sound absorption is also absorbed by the porous sound absorption function of the air-permeable base material 11, and when applied to the molded ceiling 10, can greatly contribute to quietness in the vehicle interior. .

Further, if a nonwoven fabric with a low weight is used as the skin 12, the same sound absorbing performance can be obtained, and the weight and cost can be reduced. Also,
If a material having no air permeability such as a resin sheet is used as the skin 12, the skin 12 receives indoor noise and converts it into vibration, and the low-weight nonwoven fabric 13 attenuates this vibration. It is effective in reducing noise in the area.

Next, FIG. 3 shows a modification of the first embodiment of the sound absorbing material for a vehicle according to the present invention. The point is that a bonding means having air permeability is provided.

In the second embodiment, a spider web-like hot melt 14 is inserted as the air-permeable bonding means. For example, when the base material 11 and the low-density nonwoven fabric 13 are compatible with each other, for example, when the same type of resin such as a PP resin is used, even if the structure shown in FIG. If the compatibility between PP and PA cannot be expected much, such as PP and PA, strong adhesion between the base material 11 and the low-density nonwoven fabric 13 is achieved by using a spider web-like hot melt 14.

Since the web-like hot melt 14 has air permeability, like the non-air permeable film 2,
Since the room noise is not blocked, the sound absorbing performance of the base material 11 can be improved.

Next, FIGS. 4 and 5 show a second embodiment of the present invention. First, FIG.
That is, in addition to the configuration in which the bulky and flexible low-density nonwoven fabric 13 is interposed between the base material and the skin 12, in addition, a ventilation prevention means such as a ventilation prevention film 15 is provided on the back surface side of the base material 11. ing.

Although not shown, if the adhesiveness between the base material 11 and the low-density nonwoven fabric 13 is poor, an air-permeable adhesive layer such as a spider web hot melt 14 may be inserted.

Therefore, when the entire structure is made of a breathable structure in order to enhance the sound absorption, there is a disadvantage that dust and dirt in the room are easily adhered due to the filter action of the skin 12 and the dirt is conspicuous. , And a ventilating film 1
By taking the ventilation stop means such as 5, it is possible to prevent the adhesion of dust, dust, etc. due to the filter action of the epidermis 12,
When the surface of the product is not conspicuously stained and the air venting means is taken, the base material 1 is passed through the skin 12 from the vehicle interior.
1 is partially absorbed by the low-density nonwoven fabric 13 and the porous sound absorbing function of the base material 11, and the noise reflected by the hot melt film 15 is also reduced by the base material 11 and the low-density nonwoven fabric 13. Thus, sound can be absorbed again, a sound absorbing effect can be expected at both the time of incidence and the time of reflection, and the sound absorbing performance can be further improved.

FIG. 5 is a development of the above-described embodiment, in which a back non-woven fabric 16 is attached to the back surface of the hot melt film 15 to prevent rubbing with the panel.

FIGS. 6 and 7 show a third embodiment of the present invention. The low-density nonwoven fabric 13 laminated and integrated on the surface of the substrate 11 is subjected to coloring or printing. This is a low-cost type in which the skin 12 of the above-described embodiment is eliminated as a substitute for the skin.

The coloring process may be performed on the entire low density nonwoven fabric 13 or only on the surface.
This method is cheaper if a rough surface appearance is desired.

Further, as shown in FIG. 7, if a ventilation-preventing film 15 is attached to the back surface of the base material 11 based on a two-layer laminate of the base material 11 and the low-density nonwoven fabric 13, dust, dust, etc. Does not adhere, and the sound absorption performance is also at the time of incidence and reflection,
Since each can be expected, the sound absorption performance can be improved.

Next, the sound absorbing performance of the vehicle sound absorbing material according to the present invention and the conventional sound absorbing material will be compared.

The sample A of the present invention has the structure shown in FIG. In this case, as a sample A, a raw mat made of a mixture of 55 parts by weight of glass fiber and 45 parts by weight of PP fiber as the base material 11 was subjected to a heat treatment,
A product formed by cold press molding and having a basis weight of 800 g / m ² is used.

The basis weight of the low-density nonwoven fabric 13 is 100
g / m ² , the skin 12 is a tricot cloth, the hot melt film 15 is 70 μm in thickness, the back nonwoven fabric 16 is a polyester nonwoven fabric, and the basis weight is 20 g / m ² .

On the other hand, in the conventional example, the sample having the structure shown in FIG. 9 was used as a sample B, and the substrate was the same as the product of the present invention, and the hot melt film laminated on the surface side of the substrate was:
The skin uses a tricot cloth with a thickness of 120 μm,
On the back side of the substrate, a back side non-woven fabric and a polyester non-woven fabric are used.

FIG. 8 is a graph showing the sound absorption coefficient of the product of the present invention (sample A) and the conventional product (sample B) measured from a low frequency range to a high frequency range.

As is clear from the graph of FIG. 8, it can be understood that the sound absorption coefficient of the product of the present invention is remarkably improved with respect to noise in the middle frequency range to the high frequency range.

[0054]

As described above, the soundproofing material for vehicles according to the present invention has a structure in which a bulky and flexible low-density nonwoven fabric is interposed between a base material and a skin, so that the skin is improved. In the case of breathability, a porous sound absorbing function is obtained, and in the case of non-breathable skin, the vibration of the skin can be attenuated by a low-density nonwoven fabric, so that sound absorption performance can be increased, and quietness in the vehicle interior is greatly improved It has the effect of being able to contribute.

Furthermore, if a structure is used in which a low-density nonwoven fabric having bulk and flexibility is used as a substitute for the skin on the surface of the base material, high sound absorbing performance can be obtained while the cost is reduced and the weight is reduced. Has an effect.

In addition, when a non-breathable film is adhered to the back surface of a base material having breathability, dust or dirt is applied to the surface of the product.
The surface of the product can be maintained beautifully without the attachment of dust, etc., and the noise entering the low-density nonwoven fabric and the base material is reflected by the air-stopping film in an attenuated state, and the noise is returned by the base material and the low-density nonwoven fabric. Since sound is absorbed, there is an effect that higher sound absorbing performance can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment in which a vehicle soundproofing material according to the present invention is applied to a molded ceiling.

FIG. 2 is a cross-sectional view showing the configuration of the first embodiment of the vehicle soundproofing material according to the present invention.

FIG. 3 is a cross-sectional view illustrating a modification of the first embodiment of the vehicle soundproofing material according to the present invention.

FIG. 4 is a cross-sectional view showing a second embodiment of the vehicle soundproofing material according to the present invention.

FIG. 5 is a cross-sectional view showing a configuration of a modified example of the second embodiment of the vehicle soundproofing material according to the present invention.

FIG. 6 is a sectional view showing a configuration of a third embodiment of a vehicle soundproofing material according to the present invention.

FIG. 7 is a cross-sectional view showing a modification of the third embodiment of the vehicle soundproofing material according to the present invention.

FIG. 8 is a graph comparing the sound absorbing coefficient of the sound absorbing material for vehicles according to the present invention and the sound absorbing material of the related art.

FIG. 9 is a cross-sectional view showing a configuration of a conventional sound absorbing material for a vehicle.

FIG. 10 is a cross-sectional view showing a configuration of a conventional sound absorbing material for a vehicle.

FIG. 11 is a cross-sectional view showing a configuration of a conventional sound absorbing material for a vehicle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Molded ceiling (sound absorbing material for vehicles) 11 Base material 12 Skin 13 Low density nonwoven fabric 14 Spider web hot melt 15 Vent prevention film 16 Back nonwoven fabric

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshiyuki Shimizu 3316 Miyayama, Samukawa-cho, Koza-gun, Kanagawa Prefecture F-term (reference) 3D023 BA03 BB03 BB21 BC01 BD01 BE04 4F100 AG00 AJ01 AK01D AK07 AK41 AK46 AT00A AT00B BA03 BA04 BA07 BA10A BA10B BA10D DG01 DG11 DG15C EJ17 EJ172 EJ42 EJ422 GB33 HB00C JA15C JD02D JH01 JK16C JL10C 4L047 AA05 AA14 AA21 AA23 BA23 CA04 CA05 CA06 CA19 CB03 CB08 DA00 5D06 A103

Claims (6)

[Claims] 1. A base material (11) mounted on the indoor side of a vehicle body panel (20), and a skin (1) located on a product surface side.
2) a bulky and flexible low-density nonwoven fabric (1)
3) A sound absorbing material for a vehicle, wherein the sound absorbing material is interposed. 2. The sound absorbing material for a vehicle according to claim 1, wherein the skin (12) is a nonwoven fabric with a low weight. 3. A skin (12) and a low-density nonwoven fabric (13).
3. The sound absorbing material for a vehicle according to claim 2, wherein the sound absorbing members are colored in the same color. 4. A bulky and flexible low-density nonwoven fabric (13) is laminated as a product skin on a surface of a base material (11) attached to the indoor side of a vehicle body panel (20). Sound absorbing material for vehicles. 5. The method according to claim 1, wherein the base material and the low-density nonwoven fabric are bonded with a gas-permeable adhesive. The sound absorbing material for a vehicle according to the above. 6. The vehicle sound-absorbing material according to claim 1, wherein a ventilation-preventing film (15) is attached to a back surface of the substrate (11).