JPH11327566A - Sound absorbing material and shielding cover - Google Patents

Abstract

(57) [Summary] [Problem] To provide a sound absorbing material made of polyester fiber and a shielding cover, which prevent water and oil absorption of water, engine oil, gear oil, light oil, gasoline, etc. and have an improved sound absorption coefficient. SOLUTION: The sound absorbing material 10 of the present invention has a structure in which a sound absorbing layer 13 made of thermoplastic resin fiber, a film 15 made of thermoplastic resin, and a nonwoven fabric 17 made of thermoplastic resin fiber are laminated. Are first and second nonwoven fabric layers (17A, 17A) made of thermoplastic resin fibers having different melting points.
17B), and has a configuration in which a first nonwoven fabric layer 17A made of a low-melting point thermoplastic resin fiber is disposed so as to face the film 15 made of a thermoplastic resin.

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 mounted around an engine or a transmission of a vehicle, and a shielding cover.

[0002]

2. Description of the Related Art In recent years, acceleration noise outside a vehicle and noise outside an idle vehicle have become social problems, and there is a movement to regulate noise. To deal with this, the surroundings of the engine and transmission, which are sound sources, are covered with a shielding cover with sound absorbing material to reduce outside noise. As this sound absorbing material, glass wool, natural cotton, hemp, synthetic fiber mixed felt, urethane foam,
Various materials such as melamine foam and polyester fiber have been used.

[0003] When installing the sound absorbing material, the environment to be used is different from that of the vehicle interior, such as a high temperature environment of 100 ° C or higher, or exposure to oil such as water, engine oil, gear oil, light oil, gasoline, etc. is there. For this reason, it cannot be used alone as a sound absorbing material, and the surface of the sound absorbing material is protected from the environment.

[0004] Among the sound absorbing materials, polyester fiber is excellent in sound absorbing characteristics and can be recycled because the material is a thermoplastic resin, and is an effective material as a sound absorbing material.
Therefore, as a protection measure against the environment such as water, engine oil, gear oil, light oil, and gasoline, as shown in FIG. Has been adopted. Also, Japanese Patent Application Laid-Open No. 8-76768
Japanese Patent Application Laid-Open Publication No. H11-139,086 discloses a sound absorbing material in which the surface of a polyester fiber or a polypropylene fiber as a sound absorbing material is treated with a silicon-based or fluorine-based oil repellent.

However, non-woven fabric or polyester (PET) fiber treated with water / oil repellency on the surface of the sound absorbing material,
By simply arranging polypropylene miscellaneous, it was not possible to completely prevent water intrusion due to high-pressure car washing during vehicle inspections and periodic inspections, and penetration of engine oil and light oil, thus limiting the parts used. In order to completely prevent intrusion of water and permeation of engine oil and light oil by high-pressure car washing, Japanese Patent Application Laid-Open No. 2-41
No. 476 discloses a configuration in which an aluminum foil is provided on the surface of a sound absorbing layer. However, it has been clarified by experiments that the sound absorption characteristics are reduced by disposing the aluminum foil on the surface of the sound absorbing material (see Japanese Patent Application Laid-Open No. 8-76768).

Here, a thickness of 20 mm and an area density of 800 g /
The results of measuring the normal incidence sound absorption coefficient of a sound absorbing material having 20 μm aluminum foil on both sides of m ² polyester fiber are shown in the graph of FIG. From this measurement result, the sound absorbing material having the aluminum foil provided on the surface of the sound absorbing layer has a peak sound absorption coefficient of 200.
0 Hz, 800 which is the most required as a vehicle.
The peak of the sound absorption coefficient is slightly higher on the high frequency side in the frequency range of ２０００2000 Hz, and the width of the peak is narrower.

[0007]

SUMMARY OF THE INVENTION Therefore, the present invention provides a sound absorbing material made of thermoplastic resin fiber, which prevents water and oil absorption of water, engine oil, gear oil, light oil, gasoline, etc. and has an improved sound absorption coefficient, and a shield. Provide a cover.

[0008]

The sound absorbing material of the present invention has a structure in which a sound absorbing layer made of resin fibers, a film made of thermoplastic resin, and a nonwoven fabric made of thermoplastic resin fibers are laminated. Further, the non-woven fabric made of thermoplastic resin fibers has first and second non-woven fabrics made of thermoplastic resin fibers having different melting points.
And a first nonwoven fabric layer made of a low-melting thermoplastic resin fiber is disposed so as to face a film made of a thermoplastic resin.

Alternatively, a thermoplastic polyurethane film is interposed between a thermoplastic resin film and a nonwoven fabric made of thermoplastic resin fibers. Alternatively, the sound absorbing layer has a configuration containing thermoplastic fibers having a low melting point.

[0010] The shielding cover of the present invention has a configuration in which the above-mentioned sound absorbing material and a fiber-reinforced thermoplastic resin are laminated and integrally formed.

This sound absorbing material is provided with a thermoplastic resin film of the same material between a sound absorbing material made of thermoplastic resin fiber and a non-woven fabric made of thermoplastic resin fiber, so that water, engine oil, gear oil, light oil, gasoline, etc. This completely eliminates the need for oil-repellent treatment on the nonwoven fabric and sound absorbing material on the surface, and improves the sound absorption coefficient by disposing the nonwoven fabric to reflect sound from the thermoplastic resin film. After use, it is possible to recycle (recycle) using the same material composition. Further, the shielding cover is formed by laminating a fiber-reinforced thermoplastic resin on the back surface side of the sound absorbing material, thereby enabling the sound absorbing material and the base material to be integrally formed.

[0012]

Embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 In this embodiment, a sound absorbing material will be described. FIG. 1 shows a sound absorbing material 1
0 is a sectional view. This embodiment shows an example in which a polyester resin is used as the thermoplastic resin. The sound absorbing material 10 has a sound absorbing layer 13 made of a thermoplastic resin fiber (for example, polyester fiber) laminated on the upper surface of a nonwoven fabric made of a thermoplastic resin fiber, for example, a nonwoven fabric 17 made of a polyester fiber. A thermoplastic resin film on the upper surface of the sound absorbing layer 13,
For example, a non-woven fabric made of thermoplastic resin fiber and a polyester non-woven fabric 17 are covered with a polyester resin film (hereinafter referred to as a PET film) 15.

The polyester nonwoven fabric 17 is formed by laminating polyester fibers having different melting points in two layers. Here, one non-woven fabric layer is made of polyester fiber having a melting point of ordinary polyester fiber of about 250 ° C., and the other non-woven fabric layer is made of polyester fiber having a melting point of as low as 170 ° C. to 180 ° C. Have been. In the drawing, the nonwoven fabric layer disposed opposite to the sound absorbing layer 13 is a first nonwoven fabric 17A, which is made of a thermoplastic resin fiber having a low melting point, and which is laminated on the first nonwoven layer 17A. Is formed of a thermoplastic resin fiber having a high (normal) melting point.

Next, a method for producing a nonwoven fabric will be described. Each of the first nonwoven fabric 17A and the second nonwoven fabric 17B separates fibers by a pre-spreading operation to form a fiber array having a directionality satisfying required performance, thereby forming a sheet-like web.

Next, in order to correct unevenness and directionality of the fiber density of the web, the web is laminated. After obtaining a predetermined thickness and basis weight by lamination, the laminated web is bonded. Depending on the required hardness, strength, softness, adhesive strength, processing temperature,
Change time, pressure, etc. And it cools and completes a nonwoven fabric.

Since polyester has poor thermal conductivity, when a sheet-shaped product is stacked after heat treatment, heat is trapped and the physical properties of the product change, so a cooling step is required. Then, the finished product is stored by rolling or the like.

The rolled non-woven fabric is cut into a desired size and used as a sound absorbing material. Sound absorbing layer 13
Is to add a low melting point (170 ° C. to 180 ° C.) polyester fiber component to a polyester fiber having a normal melting point.
Weight per unit area (area density) 800
A processed material in the shape of an open laminated board of １０００1000 g / m ² polyester fiber is used. Film 15 is 25 μm thick
Polyester resin (PET) film is used.

A method for forming the sound absorbing material 10 from the laminate will be described. (1) A basis weight (area density) containing 20 to 30% of a low-melting polyester fiber component (binder) 800 to 1000 g
/ M ² Opened laminated board shape processing material of polyester fiber is cut out to specified dimensions.

(2) Non-woven fabric having a two-layer structure (a non-woven fabric in which a second non-woven fabric 17B having a normal melting point is formed in an upper layer serving as a front surface, and a first non-woven fabric 17A having a low melting point is stacked in a lower layer serving as a back surface), and a basis weight of 160 g / M ² polyester non-woven fabric is cut to the specified dimensions. Here, as the low melting point polyester fiber, for example, Kanebo synthetic fiber NW100T16
0-230: There is a trademark name. PET 25μm thick
A film (eg, PET film made by Unitika Ltd.) is cut out to a specified size.

(3) The cut P is applied to one side (front side) of the opened polyester fiber-shaped laminated plate-shaped processed material.
A stack of the ET film and the polyester non-woven fabric is placed, and the cut polyester non-woven fabric is stacked on the other surface (back side). The far-infrared lamp 55 is placed in a far-infrared heating furnace 50 provided at regular intervals, and the temperature is 220 to 230 ° C.
And heat for a specified time. …… See Figure 3

At this time, the low-melting-point polyester fiber in the material to be the sound absorbing layer cut out of the opened laminated plate-shaped processed material is melted, and the PET film 15 and the nonwoven fabric 1 on the back side are melted.
7 is adhered. Further, by disposing a first nonwoven fabric 17A made of a two-layered nonwoven fabric low-melting polyester fiber so as to face the PET film 15, the first nonwoven fabric 1A is formed.
7A is melted and the PET film 15 and the second nonwoven fabric 17
B is adhered. Also, when the first nonwoven fabric 17A is disposed so as to face the sound absorbing layer, the first nonwoven fabric 17A is melted and the second nonwoven fabric 17B and the nonwoven fabric 1B are disposed on the back side of the sound absorbing layer.
3 is adhered.

(4) Next, the laminate is heated to a temperature of 50 to 80 ° C.
And press-mold. ... See FIG. 4 (5) After removing the molded product from the mold 60, the outer peripheral surface is punched to form the sound absorbing material 10 shown in FIG.

Here, polyester fibers are shown as the material of the thermoplastic nonwoven fabric and the sound absorbing layer, but other materials such as polypropylene and nylon may also be used. Further, polypropylene may be used as the thermoplastic resin film in addition to polyester. In addition, the sound absorbing layer may be in the form of a nonwoven fabric or a web, and the content of the low melting point fiber is preferably 20 to 50% by weight.

The sound absorbing effect of the thus constructed sound absorbing material was compared with that of a conventional sound absorbing material in which the sound absorbing layer was covered with a water- and oil-repellent treated polyester nonwoven fabric. The results are shown in the graph of FIG. The sound absorption coefficient of the sound absorbing material of the present invention is indicated by ○, and the sound absorption coefficient of the conventional sound absorbing material is indicated by □.

The sound-absorbing material of the present invention has a peak sound absorption coefficient for a sound having a frequency of 800 Hz to 2000 Hz required for a vehicle. On the other hand, in the sound absorbing effect of the conventional sound absorbing material, a frequency higher than a frequency required as a vehicle has a peak sound absorbing coefficient.

As described above, this sound absorbing material completely covers the sound absorbing layer with a PET film to completely prevent water and oil absorption of water, engine oil, gear oil, light oil, gasoline, etc.
The oil-repellent treatment of the nonwoven fabric or the sound absorbing material on the surface is not required, and the sound reflected by the film is absorbed by the nonwoven fabric, thereby improving the sound absorbing efficiency for the sound of the required frequency. In addition, by using the same material for the sound absorbing layer, the synthetic resin film, and the nonwoven fabric, the material can be easily recycled (recycled) after use. However, if you do not pursue recycling, sound absorbing layers, synthetic resin films,
Each of the thermoplastic resin films may be formed of a different material.

Next, another embodiment of the sound absorbing material will be described below. Example 1 (see FIG. 6) The sound absorbing material of this example strengthens the adhesion between the PET film and the sound absorbing layer made of polyester fiber. This sound absorbing material 20 has a polyurethane film 22 interposed between a PET film 25 and a sound absorbing layer 23 made of polyester fiber.

A method of forming the sound absorbing material will be described. (1) A basis weight (area density) containing 20 to 30% of a low melting point polyester resin component (binder) 800 to 1000 g
/ M ² Open material of specified dimensions is cut out from a processed material in the form of an open laminated laminate of polyester fibers.

(2) Two-layer polyester non-woven fabric having a basis weight of 160 g / m ² (normal polyester non-woven fabric on the front surface, low-melting polyester non-woven fabric on the back surface (for example, Kanebo synthetic fiber NW100T-60-230 ... trade name), thickness Sa2
5 μm thermoplastic PET film (for example, Unitika P
ET film: trade name), thermoplastic polyurethane resin film with a thickness of 40 μm (made by Ozaki Light Chemical Co., Ltd .: trade name)
Cut out to the specified dimensions.

(3) A polyurethane film 22, a PET film 25, and a two-layer nonwoven fabric 27 are polymerized in this order on one surface (front surface side) of the cut polyester fiber to be the sound absorbing layer 23. The two-layer nonwoven fabric 27 is polymerized on the back side) and heated at a temperature of 220 to 230 ° C. for a specified time. In the two-layer polyester nonwoven fabric, a low-melting polyester layer is laminated so as to face the sound absorbing layer.

At this stage, the low-melting polyester of the two-layer nonwoven fabric 27 and the sound absorbing layer 23 melts and functions as an adhesive. Further, the polyurethane film 22 is brought into a molten state by heating and functions as an adhesive between the sound absorbing layer 23 and the PET film 25.

(4) Next, it is placed in a mold at a temperature of 50 to 80 ° C. and compression-molded. (5) After removing the molded product from the mold, the outer peripheral surface is punched to form a sound absorbing material.

The sound absorbing material 20 shown in this embodiment is for the purpose of strengthening the adhesion between the PET film 25 and the sound absorbing layer 23 by melting the polyurethane film 22.

Embodiment 2 See FIG. 7 This sound absorbing material 40 shows an example in which one layer of a synthetic resin nonwoven fabric is disposed on the surface of the sound absorbing layer. (1) A basis weight (area density) containing 20 to 30% of a low melting point polyester resin component (binder) 800 to 1000 g
/ M ² Open material of specified dimensions is cut out from the processed material of the open fiber laminate of polyester fiber.

(2) Single-layer polyester nonwoven fabric having a basis weight of 50 g / m ² (for example, 90503KSO manufactured by Unitika Ltd.)
(Product name), thermoplastic polyurethane film with a thickness of 40 μm, thermoplastic polyester resin (PE with a thickness of 25 μm)
T) Cut the film to the specified dimensions.

(3) A polyester film 45, a polyurethane film 42, and a polyester nonwoven fabric 46 having predetermined dimensions are laminated on one side (front side) of a fiber-opened laminated plate-shaped material of the polyester fiber to be the sound absorbing layer 43. Sound absorbing layer 43
A polyurethane film 42 and a polyester nonwoven fabric 46 are laminated on the other surface (back surface side). Heat at a temperature of 220-230 ° C for a specified time.

At this stage, the polyurethane film 42 is melted, and the back surface of the sound absorbing layer 43 is bonded to the PET nonwoven fabric 46, and the nonwoven fabric 46 is bonded to the surface of the sound absorbing layer 43 via the PET film 45. (4) Next, it is placed in a mold at a temperature of 50 to 80 ° C and compression-molded. (5) After removing the molded product from the mold, the outer peripheral surface is punched. As the sound absorbing material 40 shown in this embodiment, a nonwoven fabric made of polyester fiber having a normal melting point is used, but the polyurethane film 42 melts and plays a role of an adhesive.

The sound absorbing materials shown in the above-described embodiments also cover the sound absorbing layer with a PET film to completely prevent water and oil absorption of water, engine oil, gear oil, light oil, gasoline, etc. Oil-repellent treatment is not required, and the sound absorption efficiency is improved. After use,
Reproduction (recycling) is facilitated by the configuration of the same material.

Embodiment 2 In this embodiment, a shielding cover using the sound absorbing material of Embodiment 1 will be described. The shielding cover 100 is configured by bonding a sound absorbing material and a base material made of a synthetic resin sheet.

As the base material, a glass fiber reinforced polypropylene standing bubble sheet material having a basis weight of 1000 g / m ² is used, and is arranged on one side (back side) of the sound absorbing material.

Embodiment 1 FIG. 8 A method for manufacturing the shielding cover 100 of Embodiment 1 will be described. (1) A basis weight (area density) containing 20 to 30% of a low melting point polyester resin component (binder) 800 to 1000 g
/ M ² polyester fiber is cut out to the specified dimensions from the processed material.

(2) A second non-woven fabric 170B made of ordinary polyester to be the front surface and a first non-woven fabric 170A made of low-melting polyester to be the back surface are laminated.
Layer nonwoven fabric, basis weight 160 g / m ² (for example, Kanebo synthetic fiber NW100T160-230 ... trade name), thickness 2
5 μm thermoplastic polyester resin (PET) film (for example, PET film made by Unitika Ltd., trade name), thickness of 1 mm, weight per unit area of 1000 g / m ² glass fiber reinforced polypropylene stamping sheet with 55% glass fiber (made of Capela sheet ... ... Trademark name) is cut out to the specified dimensions.

(3) A polyester film 150 cut out and a polyester nonwoven fabric 170 having a two-layer structure are formed on one side (front side) of the polyester fiber to be the sound absorbing layer 130.
A, 170B are laminated, and the cut glass fiber reinforced polypropylene stampable sheet 190 is laminated on the other surface (back surface side) of the sound absorbing layer 130. This laminated thing,
Heat at a temperature of 220 to 230 ° C. for a specified time.

(4) Next, it is placed in a mold at a temperature of 50 to 80 ° C. and compression-molded. (5) After removing the molded product from the mold, the outer peripheral surface is punched.

The shielding cover 100 has the sound absorbing layer 130
Covering with ET film 150 completely prevents water and oil absorption of water, engine oil, gear oil, light oil, gasoline, etc., and eliminates the need for oil-repellent treatment on non-woven fabric 170 and sound absorbing material on the surface, and improves sound absorption efficiency. Have achieved. Also,
The glass fiber reinforced polypropylene standing bubble sheet of the base material 190 reinforces the sound absorbing material 130 so as to have vibration resistance against shaking, vibration and the like. Furthermore, the shielding cover 10 is integrally formed with the sound-absorbing material 130 by using a glass fiber reinforced polypropylene foam sheet as the base material 190.
0 can be configured.

The glass fiber reinforced thermoplastic resin stampable sheet as the base material can be technically made of not only the above-mentioned polypropylene resin but also a polyester resin material as the matrix resin. When the integrally molded article of the sound absorbing material and the base material is reproduced, the reproduction is facilitated by using the same synthetic resin as the sound absorbing material made of the polyester resin.

Embodiment 2 See FIG. 9 The shielding cover 200 of this embodiment uses a nonwoven fabric having a normal melting point temperature as the surface of the sound absorbing material and has a basis weight of 100%.
A glass fiber reinforced polypropylene stamped bubble sheet material of 0 g / m ² is provided as a base material 290.

The manufacturing method will be described. (1) A basis weight (area density) containing 20 to 30% of a low melting point polyester resin component (binder) 800 to 1000 g
/ M ² polyester fiber is cut out to the specified dimensions from the processed material.

(2) Single-layer polyester nonwoven fabric with a basis weight of 50 g / m ² (90503KSO manufactured by Unitika), thickness 4
0 μm thermoplastic polyurethane film, thickness 25 μm
Thermoplastic polyester resin (PET) film, thickness 1 mm, basis weight 1000 g / m ² , glass fiber content 55%
Cut out the glass fiber reinforced polypropylene stabbable sheet (made by Cape La Sheet) to the specified dimensions.

(3) A cut polyester film 250, a polyurethane film 220, and a polyester nonwoven fabric 270 superposed on one surface (front side) of a processed material of polyester fiber to be the sound absorbing layer 230, and the other side (back side) And a glass fiber reinforced polypropylene foam bubble sheet 290 is placed on the sheet and heated at a temperature of 220 to 230 ° C. for a specified time.

(4) Next, it is placed in a mold at a temperature of 50 to 80 ° C. and compression-molded. (5) After removing the molded product from the mold, the outer peripheral surface is punched.

The shielding cover 200 has the features of the sound absorbing material of the first embodiment, and the thermoplastic polyurethane film functions as an adhesive, and makes the adhesion between the adsorption layer and the nonwoven fabric strong.

[0054]

The present invention has the following effects. 1) In the sound-absorbing material and the method for producing the sound-absorbing material of the present invention, since a laminated material of a thermoplastic synthetic resin film of the same material as the sound absorbing material is provided on the surface of the sound absorbing material, water, engine oil,
Water absorption and oil absorption of gear oil, light oil, gasoline, etc. can be completely prevented. By eliminating the need for an oil-repellent treatment on the nonwoven fabric or the sound absorbing material, it is possible to achieve an improvement in the sound absorption coefficient in the frequency range required for a vehicle. Further, by making the sound absorbing material of the same material, it is easy to reproduce (recycle) after use.

2) Since the shielding cover of the present invention is formed by laminating a fiber-reinforced thermoplastic resin on a sound absorbing material, it is possible to integrally mold the sound absorbing material and the base material.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sound absorbing material.

FIG. 2 is an explanatory view of a laminating step.

FIG. 3 is an explanatory view of a heating step.

FIG. 4 is an explanatory view of a compression molding step.

FIG. 5 is a graph comparing the sound absorbing coefficient of the sound absorbing material of the present invention with that of a conventional sound absorbing material.

FIG. 6 is a structural explanatory view of another embodiment of the sound absorbing material.

FIG. 7 is a structural explanatory view of another embodiment of the sound absorbing material.

FIG. 8 is a diagram illustrating a configuration of a shielding cover.

FIG. 9 is a configuration explanatory view of another embodiment of the shielding cover.

FIG. 10 is a sectional view of a conventional sound absorbing material.

FIG. 11 is a graph showing the sound absorbing efficiency of a conventional sound absorbing material.

[Explanation of symbols]

 10, 20, 40 Sound absorbing material 13, 23, 43, 130, 230 Sound absorbing layer 15, 25, 45, 150, 250 PET film 17, 27, 46, 170, 270 Nonwoven fabric 22, 42, 220 Polyurethane film 100, 200 Shielding Cover 190,290 Substrate

Claims (5)

[Claims] 1. A sound absorbing material comprising a sound absorbing layer made of thermoplastic resin fibers, a film made of thermoplastic resin, and a nonwoven fabric made of thermoplastic resin fibers laminated. 2. A non-woven fabric made of thermoplastic resin fibers is composed of first and second non-woven fabric layers made of thermoplastic resin fibers having different melting points, and a first non-woven fabric made of thermoplastic resin fibers having a low melting point. 2. The sound absorbing material according to claim 1, wherein the layer is disposed so as to face a film made of a thermoplastic resin. 3. The sound-absorbing material according to claim 1, wherein a thermoplastic polyurethane film is interposed between a thermoplastic resin film and a nonwoven fabric made of thermoplastic resin fibers. 4. The sound absorbing material according to claim 1, wherein the sound absorbing layer contains a thermoplastic fiber having a low melting point. 5. A shielding cover formed by laminating the sound absorbing material according to claim 1 and a fiber-reinforced thermoplastic resin and integrally forming the same.