Sound Absorbing Material and Structure Using the Same

Abstract

A sound absorbing material (1a) comprising a film (11) composed of a silicone rubber and a porous layer (12) (i.e., a first porous layer) laminated on the back surface of the film (11). The film (11) is made of a material which has flame retardancy and generates no noxious fume during combustion, such as a silicone rubber comprising only polysiloxane. The film (11) used is preferably one which has an oxygen index of 25 or higher, which exhibits a heat release value of combustion per unit volume of 8 MJ / m or less and which exhibits a heat release rate of combustion of [200 kW / m2]·10 sec or less. The first porous layer (12) is formed from a material having flame retardancy, such as glass wool, rock wool or a mixture thereof. A structure (3a) can be formed by providing the sound absorbing material (1a) having the construction described above on a rigid wall (2) in parallel, with the first porous layer (12) facing to the rigid wall (2).

Description

TECHNICAL FIELD[0001]This invention relates to a sound absorbing material and a structure using the same. In particular, this invention relates to the sound absorbing material and the structure using the same which absorbs noise of high-frequency band beyond 200 Hz as well as low-frequency band of 200 Hz or less effectively and can improve the degree of freedom of the product form.[0002]Heretofore, as the sound absorbing material of this kind, (a) the thing which uses a porous layer comprising a glass wool or a rock wool, and so on; (b) the thing which has an air layer in the sound source side; (c) the thing which has an air layer in the sound source side of the sound absorbing material; (d) the thing which laminates the aggregates of the high density and low density fibers more than at least two layers that the air permeability are different approximately 5-100 times; are known (for example, refer to patent document No. 1).[0003]However, in the sound absorbing materials of (a) and ...

AI Technical Summary

Benefits of technology

[0033]According to the sound absorbing material and the structure using the same form the first feature to the eighteenth feature of this invention, there are following effects.

[0034]First, because the flame retardancy which fits the standard of the flame retardancy of the Building Standard Law is given to the sound absorbing material itself, this sound absorbing material can be arranged in the place where the flame retardancy is needed.

[0035]Second, because neither the halogen system flame retardant nor the lead c is used as the flame retardant, there is no fear that the noxious fume is generated during combustion. And the sound absorbing material that the environmental preservation measures was given can be provided.

[0036]Third, according to the sound absorbing material and the structure using the same which has the porous layer in both sides of the film, the noise of high-frequency band beyond 200 Hz as well as low-frequency band of 200 Hz or less can be absorbed effectively.

[0037]Fourth, according to the sound absorbing material and the structure using the same that the film is integrated with the porous layer, the degree of freed of the product form can be i=proved.BRIEF DESCRIPTION OF THE FIGURES

[0038][FIG. 1] The sectional view of the sound absorbing material and the structure using the same in the first embodiment of this invention.

Problems solved by technology

Consequently, there was a difficult point that the weight of the sound absorbing material becomes heavy.

And, in the sound absorbing materials of (c), because there is the air layer in the sound source side of the sound absorbing material, there were difficult points that the weight of the sound absorbing material became heavy and it was necessary to widen the space.

Regarding the sound absorbing material of this kind of structure, there was a difficult point that the sufficient sound absorbing effect is not obtained in so-called low-frequency band of 100 Hz or less especially.

Therefore, it was difficult to take the prevention measures about the sound absorbing material known in the conventional technology.

However, in the sound absorbing material of this kind of structure, there were following difficult points.

First, because the flame retardancy is not given to the sound absorbing material itself, this sound absorbing material does not fit the standard of the flame retardancy of the Building Standard Law.

Second, in the glass wool which composes the porous layer, the sound absorbing effect becomes weak in the high-frequency band beyond 200 Hz or in the low-frequency band of 200 Hz or less.

Third, because the foam layer and the porous layer are composed individually, the construction on the site becomes complicated.

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