JPH08323804A - Manufacture of sound insulating board - Google Patents

Abstract

PURPOSE: To prevent the voids included in a sound absorbing board from being collapsed by injection pressure by a method wherein elastically restorable porous sound absorbing material sheet is used and the gap in a pair of molds is set at the dimension, in which the compression of the porous sound absorbing material sheet is taken into consideration. CONSTITUTION: On the cavity surface 1a of one of a pair of injection molds 1 and 2, sound absorbing material sheet 3 is set. As the sound-absorbing material 3, elastic restorable porous rubber sheet containing a large number of bubbles and having the thickness of T is used. At the combination with the other mold 2, the gap (d) between a cavity surface 2a and the surface of its opposing sound-absorbing material sheet 3 is set to the dimension, which is smaller by the anticipated amount T-t of the shrinkage of the sound-absorbing material sheet 3 having the thickness of T by injection pressure than the required thickness T of a backing board, under the condition that (t) is the thickness of the sound-absorbing material. sheet 3 compressed by injection pressure. When synthetic resin material 4 is injected through an injection port 2b, the synthetic resin material 4 fills the gap (d) under the condition that the thickness T of the sound absorbing material sheet 3 is compressed to the thickness (t) so as to form an injected layer having the thickness D.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a sound insulation plate in which a sound absorption plate and a support plate are superposed on each other.

[0002]

2. Description of the Related Art In order to manufacture a sound insulating plate in which a sound absorbing plate and a supporting plate are superposed, a method of joining the supporting plate and the sound absorbing plate by adhesion or the like has been usually used.

[0003]

Since such a joining process is time-consuming, it has been attempted to manufacture a sound insulation plate by injection molding with a sound absorbing plate inserted therein by a simple construction method. In this case, the thickness of the sound absorbing plate is compressed by the injection pressure, and a large number of air holes (air layers) contained in the sound absorbing plate (conventionally non-woven fabrics are crushed) are crushed, resulting in a significant noise absorption effect. It will be small.

[0004]

Means for Solving the Problems A porous sound absorbing material sheet made of an elastic material having resilience is arranged on a cavity surface of a mold for injection molding, and only a thickness reduction amount of the sound absorbing material sheet due to injection pressure is expected. A synthetic resin material is injected into a small space in the mold to form a support plate, the product in the mold is taken out, and the thickness of the sound absorbing sheet is naturally restored to form a sound absorbing plate. .

[0005]

According to this manufacturing method, it is possible to manufacture a sound insulating plate in which porous sound absorbing plates are stacked by a very simple and easy method called insert injection molding, and a sound insulating plate that does not deteriorate sound absorbing performance can be obtained.

[0006]

EXAMPLE An example will be described with reference to FIGS. On one cavity surface 1a of the pair of molds 1 and 2 for injection molding,
Set the sound absorbing material sheet 3. The sound absorbing material sheet 3 is a porous sheet that is elastically recoverable. In this example, a rubber sheet containing a large number of bubbles is used, and its thickness is T. In assembling the other mold 2 as shown in FIG. 1 (b), a space d between the cavity surface 2a and the surface of the sound absorbing material sheet 3 which is opposed to the mold 2 is formed so that the required thickness D of the support plate D 2 (b)}, the expected amount (T−t) in which the thickness T of the sound absorbing material sheet 3 is reduced by the injection pressure (t is the thickness of the sound absorbing material sheet 3 compressed by the injection pressure, FIG. Only a))).

As shown in FIG. 2 (a), when the synthetic resin material 4 is injected from the injection port 2b of the mold 2, the synthetic resin material 4 is filled in the space d and at the same time the sound absorbing material sheet 3 has a thickness T to t. And an injection layer having a thickness D is formed. That is, between the cavity surfaces 1a and 2a is (d + T) → (D + t)
Becomes When this product is taken out of the molds 1 and 2, the sound absorbing material sheet 3 is released from the compressive force and is naturally restored to the thickness T to become the sound absorbing plate 5, and the sound insulating plate 7 that overlaps with the support plate 6 having the thickness D { 2 (b)} is obtained.

[0008]

EFFECTS OF THE INVENTION According to this manufacturing method, by using the porous sound-absorbing material sheet which is elastically recoverable and setting the voids in the mold to a dimension that allows for compression, the insert injection molding method is used. A sound insulation plate having excellent sound absorption performance can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a diagram showing a first half process of an example.

FIG. 2 is a diagram showing a second half of the process of the example.

[Explanation of symbols]

 1, 2 Mold 3 Sound absorbing material sheet 4 Synthetic resin material 5 Sound absorbing plate 6 Support plate

Claims (1)

[Claims] 1. A method for manufacturing a sound insulation plate in which a sound absorption plate and a support plate are superposed on each other, in which a porous sound absorption material sheet made of an elastic material having resilience is arranged and supported on a cavity surface of a mold for injection molding. The thickness of the sound absorbing material sheet is reduced by the injection pressure from the prescribed size of the plate.The synthetic resin material is injected into the void in the mold formed by the expected amount, the support plate is molded, and the product in the mold is taken out. A method for manufacturing a sound insulation plate, which naturally restores the thickness of a sound absorption material sheet to form a sound absorption plate.