JPS6123397Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to improvements in soundproofing materials.

BACKGROUND ART Molded products made of resin compositions highly filled with metal powder, metal oxides, etc. are known as soundproofing materials whose main purpose is sound insulation. This type of soundproofing material has damping properties as a resin itself and is easy to be plasticized, so it overcomes the drawbacks of the metal or concrete soundproofing materials that have been mainly used in the past, namely secondary propagation noise. It does not have any disadvantages such as the occurrence of cracks or restrictions in shape. However, as mentioned above, this type of soundproofing material is highly filled, so its soundproofing properties deteriorate due to the transmission phenomenon in a specific frequency range due to coincidence effect resonance, and it is also heavy and difficult to handle. It has other drawbacks, and moreover, it cannot be used in locations that require a heat insulating function in addition to a soundproof function with thermal conductivity.

This idea was made in view of the above points,
The purpose of the present invention is to provide a light-weight sound-insulating material that not only has stable sound-insulating properties but also functions as a heat insulating material, is easy to process, and is lightweight.

That is, the sound insulation material according to the present invention is characterized by comprising a molded product made of an elastomer composition mixed with cork particles, and a high-density sound insulation layer provided on at least a portion of the surface of this molded product. .

The above-mentioned molded product is made by bonding closed-cell cork grains with a viscoelastic elastomer, which synergistically combines the air chamber insulation effect, vibration damping effect, and sound insulation effect of each cork grain. It has excellent heat insulation, vibration damping and sound insulation properties, and since it is made of a material that can be easily plasticized, it can be easily formed even into relatively complex shapes. It is lightweight.

As the above-mentioned elastomer, commercially available natural rubber, modified products of all synthetic rubbers, viscoelastic resins, etc. can be used. In particular, when oil resistance is required, nitrile rubber is used, and heat resistance is also used. If necessary, cloprene rubber, silicone rubber, etc. are excellent.

The above-mentioned high-density sound insulating layer is formed from, for example, a metal thin plate made of copper, aluminum, lead, etc., or a high-density rubber/plastic thin plate, etc., and is limited to these materials as long as the material is high-density and has some degree of flexibility. I can't. This sound insulation layer further improves the sound insulation properties of the molded product, and also serves as a reinforcing layer of the molded product and a chemical,
It is provided as a protective layer to protect the molded product from external factors such as ozone, ultraviolet rays, and heat, and is bonded to at least part of the surface of the molded product with an adhesive, adhesive, etc. They are not used, but are integrally molded and joined during molding of the molded product.

Since the sound insulation material with this structure has a sound insulation layer, it follows the mass law (transmission loss is proportional to mass) acoustically, and as mentioned above, its sound insulation properties are further improved, and the sound insulation properties of the sound insulation layer are further improved. The second-order propagated sound is attenuated and suppressed by the molded product made of elastomer composition, and the noise that passes through the sound insulation layer due to the coincidence effect is absorbed by the resonance damping effect of the cork grains, so the sound insulation properties of the sound insulation material are within the audible range. It is stable without any coincidence effect over the entire transport.

Fig. 3 shows a soundproofing material according to the present invention, which is made by molding nitrile rubber mixed with cork grains 1 at a weight ratio of about 40% into a plate shape with a thickness of 6 mm.
and a sound insulating layer 4 made of a thin iron plate with a thickness of 0.8 mm, which is bonded to the molded product 2 with a double-sided adhesive tape 3.

When the sound transmission loss of the soundproofing material having such a structure was measured, it showed stable soundproofing characteristics without any coincidence effect over the entire audible sound range, as shown by -Δ- in FIG. Molded product 2 for comparison
The individual sound transmission loss (indicated by -〇-) and the individual sound transmission loss (indicated by -x-) of the sound insulating layer 4 were measured and shown in the figure. 200Hz from Figure 4
It can be seen that the absorption of the sound insulating layer is clearly suppressed in the vicinity of 800 Hz due to the combination with molded material 2.

1 and 2 show an example in which the soundproofing material 5 according to the present invention is applied to an automobile. In the figure, 6 is an engine, and 7 is an exhaust system such as an exhaust pipe and a contact converter, from which noise and heat are generated.

The soundproofing material 5 of the present invention is disposed in a gap between iron plates 8 constituting a car body, and is formed between a molded product 2 made of an elastomer composition mixed with cork grains 1 and the entire lower surface of the molded product 2. It is composed of a sound insulating layer 4 that is bonded to each other. In the illustrated example, a molded article 2 made of an elastomer composition mixed with cork grains 1 is bonded over the entire surface of the iron plate 8. Therefore, the noise and heat generated by the engine 6 and the exhaust system can be effectively prevented from being transmitted into the vehicle interior by the soundproofing material 5 and the molded product 2 of the present invention.
In the above application example, the sound insulating layer 4 is provided on the entire bottom surface of the molded product, but the sound insulating layer 4 may be provided on the molded product in accordance with the location where the sound insulation material is applied, for example, on both sides or the entire surface of the molded product. Alternatively, it may be provided in a part. Further, sound insulating layers made of different materials may be provided on both sides of the molded product or on arbitrary parts.

As explained above, the soundproofing material of the present invention is composed of a molded product made of an elastomer composition mixed with cork particles, and a high-density sound insulation layer provided on at least a portion of the surface of this molded product. In addition to having stable and excellent sound insulation properties, it also functions as a heat insulating material. Furthermore, it is made of a material that is lightweight and has a relatively high degree of flexibility, making it extremely easy to handle and process. By appropriately selecting the material of the material and the sound insulating layer, the sound insulating material can be used depending on the location where it will be used, so it has great practical value.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an example in which the soundproofing material of the present invention is applied to an automobile, FIG. 2 is a partially enlarged sectional view of FIG. 1, and FIG. 3 is a sectional view of a soundproofing material according to an embodiment of the present invention.
FIG. 4 is a diagram showing the sound insulation characteristics of the sound insulation material shown in FIG. 3, and the molded product and sound insulation layer that constitute this sound insulation material. 1... Cork grains, 2... Molded product, 4... Sound insulation layer.

Claims (1)

[Scope of utility model registration request] A soundproofing material comprising a molded product made of an elastomer composition mixed with cork grains, and a high-density sound insulating layer provided on at least a portion of the surface of the molded product.