JP7640230B2 - Manufacturing method for sound absorbing and insulating structure - Google Patents

Description

The present invention relates to a method for producing a sound absorbing and insulating structure using a filler that is inserted into a gap and then expands therein to fill the gap.

2. Description of the Related Art Conventionally, polyurethane foam has been filled into gaps in sound transmission paths around fenders, instrument panels, cowls, and the like in automobiles to improve sound insulation and sound absorption.
The polyurethane foam to be inserted into the gap is formed to a size equal to or larger than the gap by a certain amount, and is inserted into the gap in a compressed state while in contact with the inner surface of the gap so that it adheres closely to the inner surface of the gap after insertion. In order to facilitate insertion into the gap, the polyurethane foam is provided with a coating layer on the surface that comes into contact with the inner surface of the gap to reduce dynamic friction resistance (Patent Document 1).

JP 2013-246182 A

However, if the inner surface of the gap is uneven, it may be difficult to smoothly insert a polyurethane foam of the same size as the gap or a certain amount larger than the gap into the depths of the gap while making contact with the uneven surface inside the gap.

SUMMARY OF THE PRESENT INVETION The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to provide a gap filling material that can be easily inserted into gaps, and a filling method thereof.
In particular, the object is to provide a space filling material that can be inserted into complex or extremely small gaps after assembly of an automobile or the like, or into gaps that are difficult to fill, and a filling method thereof.

The first aspect is characterized in that the gap filling material to be inserted into a gap comprises a packaging material and an elastomer packaged in the packaging material, and the size of the elastomer in an uncompressed state is equal to or larger than the size of the gap.

A second aspect is the first aspect , characterized in that the packaging material is sealed in a state in which the elastic body is compressed to a size smaller than the gap.

A third aspect is the first or second aspect , characterized in that the elastic body is made of a flexible polyurethane foam having an open cell structure.

The present invention relates to a gap filling method, comprising inserting the gap filling material according to the second or third aspect into a gap, and then releasing the sealing of the packaging material to restore the elastic body, thereby filling the gap with the gap filling material.

According to the present invention, the void filler is inserted into the void in a state where the elastic body in the packaging material is compressed smaller than the void, so the void filler can be inserted smoothly into the void. Also, since the size of the elastic body of the air filling material in its uncompressed state is equal to or larger than the size of the void, after the void filler is inserted into the void, the sealing of the packaging material can be released by, for example, drilling a hole in the packaging material, and the elastic body can be restored to its original size, so that the void can be easily filled with the void filler.

FIG. 2 is a cross-sectional view of a gap filler and a gap according to one embodiment of the present invention. FIG. 1 is a perspective view of a gap filler according to one embodiment of the present invention. This is a cross-sectional view of FIG. 2 along line 3-3.

One embodiment of the gap filler of the present invention is shown. The gap filler 10 of one embodiment shown in Figures 1 to 3 is inserted into the gap 50 through its opening (insertion port) 51 to fill the gap 50. Figure 1 (1-1) shows the state before the gap filler 10 is inserted into the gap 50, Figure 1 (1-2) shows the state after the gap filler 10 is inserted into the gap 50, and Figure 1 (1-3) shows the state after the gap 50 is filled with the gap filler 10.
The gap 50 exists, for example, between vehicle components or between partition walls, and the inner surface 53 of the gap 50 is made up of projections and recesses, a flat surface, or the like.
In the present embodiment, the gap 50 is formed such that the distance d1 between the opposing inner surfaces of the opening (insertion port) 51 is smaller than the maximum distance d2 between the opposing inner surfaces inside the gap 50 and the minimum distance d3 of a constricted portion formed midway within the gap 50. L1 indicates the depth of the gap 50.
The gap filling material 10 comprises a packaging material 11 and an elastic body 21 that is packaged and compressed in the packaging material 11, and the packaging material 11 is sealed with the elastic body 21 in a compressed state.

The packaging material 11 is made of a material with low air permeability. Low air permeability means non-breathable or extremely low air permeability, with air permeability (JIS K6400-7 B method) of less than 3 ml/ ^cm2 /sec. A plastic film (including a sheet) is suitable for the packaging material 11. A heat-sealable thermoplastic plastic film is preferred, and examples of the plastic film include films of polyethylene, polypropylene, polyethylene terephthalate, polyurethane, etc.

The packaging material 11 is sealed by heat sealing or the like with the air removed from the packaging material 11 so that the elastic body 21 in the compressed state does not return to its original state within the packaging material 11. The form of the packaging material 11 is not limited, and examples include a plastic film tube (cylindrical body) with both ends open, and a bag body formed by joining the outer periphery of two plastic films by heat sealing or the like. Note that a method for manufacturing the void filling material 10 using a plastic film tube or two plastic films will be described later. When the packaging material 11 is a tube or a bag body, it is preferable that the size of the packaging material 11 is approximately equal to the size of the elastic body 21 in the uncompressed state so as not to hinder the return of the elastic body 21 when the sealing is released.

The elastic body 21 has a size equal to or larger than the gap 50 in an uncompressed state, and is packaged in the packaging material 11 in a state compressed to a size smaller than the gap 50. The elastic body 21 of this embodiment has a thickness in an uncompressed state that is equal to or larger than the maximum distance d2 within the gap 50.
The elastic body 21 is not particularly limited in material as long as it has elasticity that allows compression and restoration. Examples of the elastic body 21 include foams such as polyurethane foam, olefin foam, and rubber sponge, and fiber cushions. In particular, polyurethane foam is a preferred material because it has excellent restoration and distortion characteristics, and sound absorption and sound insulation properties can be easily controlled.

When the elastic body 21 is made of polyurethane foam, the polyurethane foam is preferably a soft polyurethane foam having an open cell structure in order to improve compressibility and restorability. The density (JIS K7222) of the soft polyurethane foam having an open cell structure is preferably 10 to 100 kg/ ^m3 , more preferably 15 to 40 kg/ ^m3 . The 25% hardness (JIS K6400-2 6.7D method) of the soft polyurethane foam having an open cell structure is preferably 20 to 300 N, more preferably 30 to 150 N. If the soft polyurethane foam having an open cell structure is too hard, the force pressing the inner surface 53 of the voids 50 when restored becomes too strong, and the inner surface 53 of the voids 50 may be deformed depending on the material and thickness of the inner surface 53. The air permeability (ASTM D 3574) of the flexible polyurethane foam having an open-cell structure is preferably 3 to 300 L/min, more preferably 15 to 200 L/min, since if the air permeability is too low, the flexible polyurethane foam having an open-cell structure will be distorted significantly and the recovery property will be reduced, whereas if the air permeability is too high, it will be disadvantageous in terms of sound absorption and sound insulation.

As a flexible polyurethane foam having an interconnected cell structure, a slab-foamed flexible slab is preferred. Slab foaming is a foaming method in which polyurethane foam raw material is fed onto a conveyor and foamed at room temperature. The slab-foamed flexible polyurethane foam is cut to a thickness and shape appropriate for the voids and used as the elastic body 21.

The gap filling material 10 can be manufactured by packaging the elastic body 21 in the packaging material 11, compressing the elastic body 21, and then sealing the opening of the packaging material 11 with a heat seal or the like after removing the air from inside the packaging material 11.
For example, when the packaging material 11 is a tube made of plastic film, the elastic body 21 is placed into an opening at one end of the tube, and pressure is applied to and compressed by the outside of the tube to remove the air from inside the tube. In this state, the openings at both ends of the tube are sealed by heat sealing or the like to maintain the compressed state of the elastic body 21.
On the other hand, when two plastic films are used for the packaging material 11, the elastic body 21 is sandwiched between the two plastic films, and pressure is applied to and compressed by the outside of the two plastic films to remove the air between the two plastic films. In this state, the two plastic films are heat-sealed at the outer periphery away from the edge of the elastic body 21 to seal the same, thereby maintaining the compressed state of the elastic body 21.
The sealing position of the packaging material 11 is set at a position a predetermined distance away from the outer periphery of the elastic body 21 in the compressed state so that the elastic body 21 can restore to its size before being uncompressed.
When removing air from the packaging material 11, a suction device may be connected to the opening of the packaging material 11 to discharge the air inside the packaging material 11 to the outside.

A method of filling a gap using the gap filling material 10 will be described. For example, as shown in Fig. 1, the gap filling material 10, which is in a compressed state of an elastic body 10 wrapped in a wrapping material 11, is inserted into a gap 50 through an opening 51 of the gap 50.
In this case, since the elastic body 21 wrapped in the packaging material 11 is compressed to be smaller than the gap 50, the overall size of the gap filler 10 is smaller than the gap 50, and since the gap filler 10 is compressed to be smaller than the opening (insertion port) 51, when the gap filler 10 is inserted into the gap 50, there is no or little friction between the opening (insertion port) 51 of the gap 50 and the inner surface 53 of the gap 50, and the gap filler can be inserted smoothly.

After inserting the gap filler 10 into the gap 50, the sealing of the packaging material 11 of the gap filler 10 is released. The sealing of the packaging material 11 is released by making a hole in the packaging material 11 with a punching tool 61 such as a needle, or by cutting a part of the packaging material 11 with a blade or the like.
When the packaging material 11 is unsealed, outside air flows into the packaging material 11, the compression of the elastic body 21 is released, and the elastic body 21 returns to its original state.

The size (e.g., length, thickness) of the elastic body 21 before compression (uncompressed state) is approximately equal to or a predetermined amount larger than the size of the gap 50 (e.g., depth and height of the inner surface of the gap), so that the gap 50 is filled with the gap filling material 10 when the elastic body 21 is restored to its original state by unsealing the packaging material 11.

A flexible polyurethane foam (slab foam) having an open cell structure, density 25 kg/m ³ , air permeability 30 L/min, product number: Calmflex F-2, manufactured by Inoac Corporation, was cut into a rectangular parallelepiped of thickness 40 mm × length 750 mm × width 50 mm to prepare an elastic body.
The packaging material used was a tube made of a general-purpose polyethylene film having a thickness of 50 μm (a long tube sheet having a width of 120 mm and formed into a bag shape).

An elastic body was inserted into the tube from one end, and the elastic body was compressed from the outside of the tube to a thickness of 10 mm. A suction device was connected to one end of the tube, and the air inside the tube was removed using the suction device while the other end was closed. In this state, both ends of the tube were sealed with heat sealing, and unnecessary parts were cut off, thereby producing an example of a void filler in which the elastic body was maintained in a compressed state of 10 mm in thickness in the tube (packaging material).

The prepared void filler was inserted into the void 50 shown in Figure 1, which has a height (d2) of 40 mm, a depth (L1) of 750 mm, and a width of 50 mm, and a narrow portion of height (d3) of 30 mm in part of the middle part of the depth (L1) of the gap with a height (d1) of 20 mm at the opening (insertion port) as shown in (1-1) and (1-2) of Figure 1. After insertion, a hole was made in the packaging material of the void filler with a drill (perforation tool 61), and the packaging material was unsealed. This caused the elastic body, which had been compressed up until then, to return to its original shape, and the void was filled with the void filler with the restored elastic body.

In addition, it was extremely difficult to insert the elastic base material alone, cut into a rectangular parallelepiped of thickness 40 mm, length 750 mm, and width 50 mm, without any packaging material, into the gap due to frictional resistance on the surface of the elastic body. Even if it was forcibly inserted, it could not be inserted any further than the narrow part of the middle part, which was 30 mm high.

In this way, the gap filler and filling method of the present invention can be easily inserted into gaps, and are particularly suitable for inserting and filling gaps such as complex or extremely small gaps after assembly of an automobile or other vehicle, or spaces where space filling work is difficult.

REFERENCE SIGNS LIST 10: gap filling material 11: packaging material 21: elastic body 50: gap 51: opening of gap (insertion port)
53 Inner surface of cavity 61 Punching tool

Claims (3)

A method for manufacturing a sound absorbing and insulating structure using a gap filling material that is inserted into a gap between components of a vehicle, comprising the steps of:
The void filling material comprises a packaging material and an elastic body packaged in the packaging material,
The elastic body has a size in an uncompressed state equal to or larger than the size of the void,
The packaging material is a gap filler that is sealed in a state in which the elastic body is compressed to a size smaller than the gap,
After insertion into the cavity ,
The sealing of the packaging material is released to restore the elastic body, and the gap is filled with the gap filling material.
A method for producing a sound absorbing and insulating structure, comprising the steps of: forming the sound absorbing and insulating structure into the packaging material without melting the packaging material. The method for manufacturing a sound absorbing and insulating structure according to claim 1, wherein the gap is present around a fender, an instrument panel, or a cowl of an automobile. 3. The method for manufacturing a sound absorbing and insulating structure according to claim 1 or 2, wherein the elastic body is a flexible polyurethane foam having an open cell structure, a density (JIS K7222) of 15 to 40 kg/m3, and a 25% hardness (JIS K6400-2 6.7D method) of 30 to 150 N.

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