JP3074541B2 - Damping material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping material, and more particularly to a vibration damping material capable of preventing acoustic resonance.

[0002]

2. Description of the Related Art A resin plate, a fiber reinforced resin plate, or a metal plate is used as a speaker box material or a rack material for audio equipment. As another material, a synthetic resin such as polyethylene or polypropylene and graphite powder are kneaded. An acoustic material (for example, Japanese Patent Publication No. 58-56316), a ceramic molded body using a thermosetting resin or rubber as a binder (for example, Japanese Patent Application Laid-Open No. 55-79797), and a fibrous metal piece were deposited. An acoustic material obtained by post-compression and bonding fibrous metal pieces to each other (for example, JP-A-57-79796).
No.).

[0003]

The resin plate and the fiber-reinforced resin plate are excellent in moldability and weight reduction, but because of their light weight, they tend to resonate and are affected by external vibrations. There is a problem that it is easy. A metal plate such as aluminum cannot sufficiently attenuate high-frequency resonance, and has a problem that resonance easily occurs at a specific frequency. The acoustic material obtained by kneading a synthetic resin and graphite powder has a low Young's modulus and a small density, cannot sufficiently prevent resonance, and a ceramic molded body using a binder is expensive and requires a molding method. However, there is a problem in that the acoustic material on which the compressed fibrous metal pieces are deposited has a low density, so that resonance cannot be sufficiently suppressed in applications such as a speaker box. Therefore, the present invention has been made in order to solve such a problem, acoustic resonance is prevented,
It is intended to provide a vibration damping material having good acoustic characteristics and good workability.

[0004]

The vibration damping material of the present invention is provided between a first layer and a third layer formed from a hard board.
Metal powder 25 to 100 parts by weight of organic binder
The surface of a hardboard molded body integrally formed by pressure molding with a second layer mixed with 300 parts by weight interposed therebetween is coated with any one of melamine, acrylic and vinyl chloride.

(1) Hard board As the hard board, Japanese Industrial Standard "Hard fiber board" A
Those conforming to 5907 are used. (2) Organic Binder As the organic binder, one or more of epoxy resin, polyurethane resin, unsaturated polyester resin, polyacrylester resin, amino resin, urea resin, and phenol resin are used. (3) Metal Powder As the metal powder, one or more metal powders of aluminum, copper, brass, zinc, titanium, stainless steel, nickel, steel, cast iron and alloys thereof are used, and preferably 300 mesh or less. Organic binder 10
25 to 300 parts by weight is added to 0 parts by weight.
When the amount exceeds the weight part, the bulk specific gravity of the molded hardboard becomes large, and the flexibility is lost. (4) Coating layer As the coating layer, any one of melamine, acrylic, and vinyl chloride is used. The coating layer improves the sound quality, improves the appearance, and particularly uses easily oxidizable iron powder. In this case, it is possible to prevent oxidation and to prevent poor appearance over time.

[0006]

The vibration damping material of the present invention has vibration damping performance against acoustic vibration, and the energy of the vibration transmitted to the vibration damping material is converted into thermal energy by mutual friction between the organic binder and the metal powder. Is attenuated.

[0007]

An embodiment of the present invention will be described. A second layer formed by adding 200 parts by weight of a cast iron powder (300 mesh) to 100 parts by weight of a phenol resin between a first layer and a third layer formed from two hard boards (T350). After the intervening, pressure molding was performed to form a hardboard molded body having a thickness of 11 mm, and then a melamine sheet having a thickness of 0.5 mm was adhered to the surface of the molded body to form a hardboard molded body having a thickness of 12 mm. A diaphragm was obtained. The comparative material is an aluminum plate having a thickness of 12 mm. Next, the loss coefficient (η) of the vibration damping material of the present example and the aluminum plate of the comparative example were measured, and the results are shown in the following table. It can be seen that the present example has a larger loss coefficient (η) than the comparative example, and has a good vibration damping effect.

[0008]

[Table 1]

Next, a speaker box was produced using the vibration damping material of the present invention and an aluminum plate as a comparative material, and a viewing test was carried out. It was confirmed that it exhibited acoustic characteristics.

[00010]

According to the present invention, an organic binder 1 is provided between a first layer and a third layer formed from a hard board.
One of melamine, acrylic, and vinyl chloride is applied to the surface of the hardboard molded body integrally formed by press-molding with a second layer in which metal powder is mixed in an amount of 25 to 300 parts by weight with respect to 00 parts by weight. Because of the coating, the vibration damping effect, decorativeness and workability are excellent, and the acoustic characteristics are good. In addition, since the raw material is inexpensive, the production cost can be reduced.

Continuation of the front page (56) References JP-A-1-313351 (JP, A) JP-A-3-137354 (JP, A) JP-A-54-5403 (JP, A) JP-A-61-202500 (JP) , U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G10K 11/16-11/178 H04R 1/02 101-103

Claims (2)

(57) [Claims] 1. A pressure-molding method in which a second layer in which 25 to 300 parts by weight of a metal powder is mixed with 100 parts by weight of an organic binder is interposed between a first layer and a third layer formed from a hard board. One of melamine, acrylic, or vinyl chloride on the surface of the hardboard
A damping material characterized by being coated with a seed. 2. The damping material according to claim 1, wherein the thickness of the coating layer is 0.5 mm.