JP2001242873A - Soundproofing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soundproofing material for vehicles which is capable of tremendously improving a soundproof effect as a barrier between an engine room and cabin of, for example, an automobile and as other barriers. SOLUTION: The soundproofing material 1 for vehicles is a hollow double wall structure formed with a hollow section 4 between an inner wall 2 and outer wall 3 facing each other. A sound attenuating material 5 for changing sound energy to kinetic energy is packed into the hollow section 4. The packing density of the sound attenuating material 5 is 0.01 to 0.1 g/cm3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproofing material requiring a high soundproofing effect, such as a partition wall between an engine room and a cabin of an automobile.

[0002]

2. Description of the Related Art For example, a dashboard and a toeboard are separated from an engine room of an automobile by a dashboard, and a partition formed by the board has high soundproofing so that engine noise does not reach the interior of the vehicle. An effect is required.

[0003] For this reason, there has hitherto been known a board having a hollow double-walled structure in which the hollow portion is densely filled with a foam material such as urethane resin (see Japanese Patent Application Laid-Open No. 9-99868).

[0004]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 9-998 is disclosed.
As shown in Japanese Patent Publication No. 68, a board having a hollow double-walled structure, in which a hollow portion is filled with a foaming material such as urethane resin, the energy transmission when sound waves are transmitted by vibration is transferred to the foaming material. To reduce the
When actually measured with a sound level meter, the sound attenuation rate of the foam material is not as effective as expected, and depending on the density of the foam material, it may be worse than that of a simple hollow double wall, It has been found that such a foam-filled type that reduces the transmission of sound energy cannot provide a sufficient soundproofing effect.

Accordingly, an object of the present invention is to reduce the transmission of vibrations due to sound as in the prior art, and to move the sound energy to the kinetic energy by moving the sound damping material itself with the sound energy. It is an object of the present invention to provide a soundproofing material that can significantly improve the soundproofing effect, for example, as a partition between an engine room and a vehicle compartment of a vehicle and other partitions by changing and consuming it effectively.

[0006]

According to the first aspect of the present invention, there is provided a soundproofing material having a hollow double-wall structure in which a hollow portion is formed between opposed inner and outer walls. The soundproof material is characterized in that the hollow portion is filled with a sound attenuation material that converts sound energy into motion energy.

According to a second aspect of the present invention, there is provided the soundproofing material according to the first aspect, wherein the soundproofing material having a hollow double wall structure is formed by blow molding a synthetic resin.

According to a third aspect of the present invention, there is provided the soundproofing material according to the first or second aspect, wherein the soundproofing material is for a vehicle.

According to a fourth aspect of the present invention, there is provided the soundproofing material according to the first, second or third aspect, wherein the sound attenuating materials have an average diameter of 1 to 5 mm and a density of 0.01 to 5 mm, which are not fixed to each other in a contact state. It is a spherical granular material of 0.2 g / cubic centimeter, and its packing density is 0.01 to 0.1 g / cubic centimeter.

According to a fifth aspect of the present invention, there is provided a soundproofing material according to the first, second or third aspect, wherein the sound attenuating materials are made of the following fibrous substances which are not fixed in contact with each other. . Length of fibrous substance: 25 to 150 mm Thickness of fibrous substance: 1 to 30 denier Density of fibrous substance: 0.01 to 0.1 g / cubic centimeter Density of fibrous substance: 0.01 to 0.1 g / Cubic centimeter

According to a sixth aspect of the present invention, there is provided the soundproofing material according to any one of the first to fifth aspects, wherein the distance between the inner wall and the outer wall of the hollow portion is 5 to 50 mm. .

According to a seventh aspect of the present invention, in the soundproofing material according to any one of the first to sixth aspects, a support portion for a filled sound attenuation material is formed in the hollow portion. Things.

[0013]

FIG. 1 is a cutaway perspective view showing a part of a vehicle soundproofing material according to an embodiment of the present invention, FIG. 2 is a detailed sectional view showing a portion within a broken line circle A in FIG. FIG. 3 is a partial view showing details of the sound attenuating material together with its operation.

A soundproofing material 1 for a vehicle according to an embodiment of the present invention has a hollow double-walled structure in which a hollow portion 4 is formed between opposed inner and outer walls 2 and 3 made of blow-molded plastic. The part 4 is filled with a sound damping material 5 which converts sound energy into kinetic energy.

The sound attenuating material 5 is a spherical granular material having an average diameter of 1 to 5 mm and a density of 0.01 to 0.2 g / cubic centimeter, and has a function of converting sound energy into motion energy. In order to keep them in contact with each other, they are not fixed, and their packing density is 0.01-0.1 g / cubic centimeter. The sound attenuating materials 5 are thus in contact with each other and in a state in which they are not fixed.
By setting the thickness to 01 to 0.1 g / cubic centimeter, transmission of sound vibration is prevented in the hollow portion 4, and the sound attenuating material 5 itself is caused to vibrate, swing, or displace by the sound energy, and the sound is attenuated. Energy can be converted into exercise energy and consumed, and the soundproofing effect can be dramatically improved (see FIG. 3).
In the illustrated embodiment, the distance between the inner wall 2 and the outer wall 3 of the hollow portion 4 is 5 to 50 mm.

As shown in FIG. 1, a support portion 6 of a filled sound attenuation material 5 is formed in the hollow portion 4 at an appropriate interval. The support portion 6 is a concave rib formed with the inner wall 2 facing the outer wall 3, but may be a partition wall having no concave rib.

The sound-attenuating material 5 may be a spherical granular material having an average diameter of 1 to 5 mm and a density of 0.01 to 0.2 g / cubic centimeter. Examples include inorganic particles such as shirasu balloons in the form of hollow particles, and plastics such as polystyrene, polyvinylidene chloride, polyolefin, polyphenylene oxide, and copolymers thereof, which are foamed into particles.

In the present invention, the sound attenuating material can be composed of the following fibrous substances. That is, the length of the fibrous substance is 25 to 150 mm, the thickness of the fibrous substance is 1 to 30 denier, and the density of the fibrous substance is 0.01 to 0.1 g / cubic centimeter. This fibrous substance includes natural fibers such as cotton, hemp, wool, and silk; regenerated fibers such as viscose rayon and copper ammonia rayon; semi-synthetic fibers such as acetate and triacetate; nylon, polyester, acrylic, vinylon, polypropylene, and polyurethane. And the like, and blended fibers thereof.

In the soundproofing material of the present invention, the sound damping material filling the hollow portion is not fixed, so that when the soundproofing material itself is rocked, the internal damping material generates a slight noise, so that the soundproofing material for vehicles is not used. In addition, it is suitable for use in fields such as soundproofing materials for houses that do not swing.

A sound-insulating material having a hollow double-walled structure in which a hollow portion is formed between opposed inner and outer walls before the sound-insulating material is filled can be obtained by blow-molding rigid plastic. Specific examples include polyethylene, polypropylene, polyamide resin, polycarbonate resin, polyethylene terephthalate resin, polybutylene terephthalate resin, ABS resin, and modified polyphenylene resin.

Here, the blow molding means that a tubular body or a sheet body in a heated and molten state of plastic is placed between molds, clamped by a mold having a cavity of a desired shape, and pressurized fluid is filled therein. It is the one that is put and shaped.

When the sound attenuating material is a granular material, it is preferable to fill the material after blow molding. Conversely, a fibrous material is preferably inserted into the parison during blow molding.

The soundproofing material having a hollow double-wall structure of the present invention is most preferably blow-molded, but is not limited to blow-molding. For example, the inner wall and the outer wall are formed as separate sheet-formed products. Needless to say, it is also possible to form them integrally by heating and welding them.

In order to see the effect of the soundproofing material according to the present invention, containers shown in the following Experimental Examples 1 to 7 were prepared, and their soundproofing properties were actually measured with a sound level meter and evaluated.

EXPERIMENTAL EXAMPLE 1 A high-density polyethylene is blow-molded to obtain a foldable container having a bottom wall and four side walls integrally formed by thin hinges on four sides of the bottom wall. Was. The four side walls of the container are latched together and have separate lids. The bottom wall, the four side walls and the lid of the container have a hollow double-walled structure, and the inside of the hollow portion has an average diameter of 1 to 3 mm and a density of 0.025 g / cubic centimeter of expanded polystyrene granules. Are packed so that the packing density is 0.01 to 0.05 g / cubic centimeter. The expanded polystyrene particles are in contact with each other, but are not fixed, and are arranged in a state where the particles can move due to external vibration. The dimensions of the container are 380x305x300,
The thickness of the side wall is 20 mm. The content of the container is about 20 liters.

Experimental Example 2: The same fibrous substance as described below was filled in the hollow double wall of the same container as in Experimental Example 1. The fibrous materials are in contact with each other but not fixed, and are arranged so as to be movable against external vibration. Average length of fibrous substance: 100 mm Average thickness of fibrous substance: 15 denier Average density of fibrous substance: 0.05 g / cubic centimeter Filling density of fibrous substance: 0.021 g / cubic centimeter

Experimental Example 3 The same container as in Experimental Example 1 was used except that the inside of the hollow double wall was filled with a two-component reactive polyurethane.

Experimental Example 4: Unexpanded expanded beads are filled in the hollow double wall of the container similar to that of Experimental Example 1, filled in a reinforcing mold such as a jig, and foaming is completed by heating with steam. The particles of the foam at this time were substantially the same as those in Experimental Example 1, but the foams were welded to each other due to steam heating, and were also welded to the hollow double wall and the foam.

Experimental Example 5: For comparison, an experiment was performed without filling the hollow double wall of the container used in Experimental Example 1.

Experimental Example 6: A molded article made entirely of expanded polystyrene, having dimensions of 385 × 315 × 260,
A container having an inner volume of about 18 liters and a wall thickness of 20 mm was used.

Experimental Example 7: The thickness was 5 m by injection molding.
m, a single-walled container having external dimensions of 375 × 335 × 230 and an internal volume of about 21 liters was used.

Measurement method: At the time of measurement, an alarm clock having a sound pressure of 76 dB was inserted as a sound source inside the container, each side of the container was sealed with packing tape, and a position 50 cm away from the container. Horizontally integrated R-type sound level meter N
L06 was installed. Then, the bell of the alarm clock was sounded and the equivalent noise level for 5 seconds was measured. Measurement is 3
Runs were performed and the average was recorded. Table 1 shows the results.

[0033]

[Table 1]

From the results shown in Table 1, the foamed polystyrene particles in the non-fixed state shown in Experimental Example 1 according to the present invention had an extremely good equivalent noise level of 57 dB. Further, when the fibrous substance shown in Experimental Example 2 according to the present invention was filled in the inside of the hollow double wall, the equivalent noise level was 52 dB and a better value was obtained. When the foamed polyurethane shown in Experimental Example 3 was filled in the hollow portion of the hollow double wall, a reasonable sound insulation was obtained, but it was more satisfactory than Experimental Examples 1 and 2 according to the present invention. Not sound-insulating.

Even if the hollow double wall is filled with expanded polystyrene, which is generally said to be excellent in sound insulation, if it is in a fixed state as in Experimental Example 4, as in Experimental Example 5, This means that sound insulation is poorer than that of a hollow double-walled state where nothing is inserted. The reason is that foamed polystyrene filling the hollow double wall is a medium that transmits vibration rather than the hollow double wall, and foamed polystyrene inserted for sound insulation impairs sound insulation. It is considered that the result was obtained. On the other hand, the one according to the present invention is also the same granular material of expanded polystyrene, but is in a contact state without being fixed to each other, and it can be judged that the free state contributes to enhancing the sound insulation. . In other words, it is judged that, in addition to the sound insulation property of the expanded polystyrene particles reducing the transmission of vibration, the sound insulation effect of converting the energy of sound into kinetic energy in its free state can be obtained.

As a matter of course, it can be seen that a single-walled injection-molded product as in Experimental Example 7 has extremely low sound insulation.

[0037]

According to the present invention, in addition to reducing the transmission of vibration by sound in the hollow portion, the sound attenuating material itself is moved by the sound energy to convert the sound energy into the movement energy. By effectively consuming and effectively attenuating, it is possible to provide a soundproofing material for a vehicle in which the soundproofing effect can be remarkably improved, for example, as a partition between an engine room and a vehicle compartment of an automobile and other partitions.

[Brief description of the drawings]

FIG. 1 is a cutaway perspective view showing a part of a vehicle soundproofing material according to an embodiment of the present invention.

FIG. 2 is a detailed sectional view showing a portion within a broken line circle A in FIG.

FIG. 3 is a partial view showing details of a sound attenuation material together with its operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle soundproof material 2 Inner wall 3 Outer wall 4 Hollow part 5 Sound attenuation material 6 Support part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2E001 DF04 FA00 GA03 GA07 GA20 GA82 HD11 JA11 JA14 JC07 JC08 JD02 JD04 JD06 3D003 AA07 CA05 DA22 3D023 BB17 BB21 BD12 BE04 BE06 BE31 5D061 AA22 AA29 BB07 BB21 BB27

Claims (7)

[Claims] 1. A soundproofing material having a hollow double-walled structure in which a hollow portion is formed between opposed inner and outer walls, wherein the hollow portion has sound attenuation that converts sound energy into kinetic energy. A soundproofing material characterized by being filled with a material. 2. The soundproofing material according to claim 1, wherein the soundproofing material having a hollow double wall structure is formed by blow molding a synthetic resin. 3. The soundproofing material according to claim 1, wherein the soundproofing material is for a vehicle. 4. The sound attenuating material has an average diameter of 1 to 5 mm and a density of 0.01 to 0.
The soundproofing material according to claim 1, 2 or 3, which is a spherical granular material of 2 g / cubic centimeter and has a packing density of 0.01 to 0.1 g / cubic centimeter. 5. The soundproofing material according to claim 1, wherein the sound attenuating material is made of the following fibrous substances which are not fixed to each other in a contact state. Length of fibrous substance: 25 to 150 mm Thickness of fibrous substance: 1 to 30 denier Density of fibrous substance: 0.01 to 0.1 g / cubic centimeter Packing density of fibrous substance: 0.01 to 0.1 g / Cubic centimeter 6. The space between the inner wall and the outer wall of the hollow portion is 5-5.
The soundproofing material according to any one of claims 1 to 5, wherein the thickness is 0 mm. 7. The hollow portion is provided with a support portion for a filled sound attenuating material.
The soundproofing material according to any one of the above.