JPH0524142A - Damping soundproof sheet for vehicle - Google Patents

Abstract

PURPOSE:To provide a damping soundproof sheet capable of improving the soundproof capacity of a low frequency region greatly. CONSTITUTION:A damping soundproof sheet 1 used in order to form a damping soundproof structure consisting of the damping layer 3 bonded to a vehicle panel 1 and the soundproof layer 5 formed on the damping layer 3 is formed into a three-layered structure consisting of the lower layer 13 becoming the damping layer 3, an intermediate layer 15a becoming a first soundproof layer 5a and a skin layer 15b becoming a second soundproof layer 5a and the intermediate layer l5a is formed from a first foamed polymer compound of an open cell formulation and the skin layer 15b is formed from a second foamed polymer compound of a closed cell formulation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to form a vibration-damping and sound-proofing structure from a vibration-damping layer attached to a vehicle panel surface (especially floor surface) and a sound-insulating layer formed on the vibration-damping layer. Regarding vibration damping and soundproofing sheet used.

[0002]

2. Description of the Related Art Conventionally, as the vibration damping and soundproofing sheet as described above, the one having the following structure has been proposed by the same applicant as the applicant (Japanese Patent Laid-Open No. 62-92965).

"A vibration-damping and sound-proofing sheet used for forming a vibration-damping and sound-proofing structure comprising a vibration-damping layer adhered to a vehicle panel surface and a sound-proofing layer formed on the vibration-damping layer. A vibration-damping layer forming material made of a system adhesive compound and a soundproofing layer forming material made of a foamed rubber compound are laminated by adhesion, and the polymer of the foamed rubber compound is 1,2-polybutadiene. .About.85 wt%, rubber content ... balance.

[0004]

However, in the case of the vibration damping and soundproof sheet having the above-mentioned structure, the soundproofing performance is not always sufficient.

Particularly, in an automobile, the low frequency region (5
It is required soundproofing performance 00~1000H _Z) is high.

In view of the above, an object of the present invention is to provide a vibration damping and soundproofing sheet capable of improving the soundproofing performance in the low frequency region.

[0007]

Means for Solving the Problems As a result of intensive efforts to develop the above problems, the inventors of the present invention have come up with a vibration damping and soundproofing sheet for vehicles having the following structure.

A vibration-damping and sound-proofing sheet used for forming a vibration-damping and sound-proofing structure comprising a vibration-damping layer attached to a vehicle panel surface and a sound-proofing layer formed on the vibration-damping layer. A lower layer to be a vibration layer, an intermediate layer to be a soundproof first layer, and a three-layer structure consisting of a skin layer to be a soundproof second layer, wherein the intermediate layer is a first foamed polymer blend of an open cell formulation. And a second foaming polymer compound having a closed cell formulation, wherein the skin layer is formed of a second foaming polymer compound.

[0009]

Detailed Description of Means Each configuration of the above means will be described in detail. In addition, compounding unit "PHR", "part", "%"
Is a weight unit unless otherwise specified.

(1) A vibration-damping and sound-proofing sheet 11 of the present invention comprises a vibration-damping layer 3 which is attached to a vehicle panel 1, and a sound-damping layer 5 which is formed on the vibration-damping layer 3. It is assumed that it is used to form (see FIG. 2).

(2) The vibration-damping and sound-proofing sheet 11 of the present invention comprises a lower layer 13 which becomes the vibration-damping layer 3 and an intermediate layer 1 which becomes the sound-damping first layer 5a.
5a and a sound-insulating second layer 5b, which is a skin layer 15b, has a three-layer structure, and the intermediate layer 15a is formed of a first foaming polymer compound having an open cell formulation, and the skin layer 15b is independent. The second requirement is a constitution formed of a second foaming polymer compound having a cell formulation.

(3) The lower layer 13 to be the vibration damping layer 3 may be a bituminous material which is a material of a conventional vibration damping sheet, but in order to reduce the weight, the same person as the applicant of the present application may be used. The following configuration proposed by the applicant is desirable (Japanese Patent Application No. 3-73).
No. 99: not yet published at the time of filing this application).

"10-100 parts of viscoelastic material, 100-500 of oriented inorganic filler per 100 parts of polymer component.
A vibration-damping sheet formed by molding a composition in which parts are blended, and further, a cross-linking agent and a foaming agent are blended, wherein the polymer component is a cross-linkable resin of 50 to 90%, and a rubber component 10. The amount of the foaming agent added is such that the expansion ratio is 1.5 to 5 times. As the crosslinkable resin, 1,2-polybutadiene,
Examples thereof include ethylene-vinyl acetate copolymer (EVA) and block copolymers of an aromatic vinyl compound and conjugated diolefin.

As the rubber component, natural rubber (N
R) or IR, BR, CR, NBR, IIR, EP
Examples include various synthetic rubbers such as DM and SBR, and recycled rubbers thereof.

Examples of the above-mentioned oriented inorganic filler include scale-like fillers such as mica, graphite and glass flake, and further inorganic fiber fillers such as glass fiber.

As the crosslinking agent, sulfur is usually used,
The compounding amount is usually 2 with respect to 100 parts of the polymer component.
0 to 50 parts. Further, the crosslinking agent may be an organic peroxide.

As the foaming agent, one used for usual rubber compounding, for example, dinitrosopentamethylenetetramine (D
PT), azodicarbonamide (ADCA), p-toluenesulfonyl hydrazide (TSH), 4,4'-oxybisbenzenesulfonyl hydrazide (OBSH)
Etc. can be used. For example, in the case of DPT, it is 1 to 5 parts per 100 parts of the polymer component. When DPT is used as the foaming agent, urea and its derivative are used as an auxiliary agent.

(4) The first foaming polymer compound forming the intermediate layer 15a is not particularly limited as long as it is an open cell formulation, but it is described in the above-mentioned JP-A-62-275743. Foam rubber compound "polymer, 1,
2-polybutadiene --- 15 to 85 wt%, rubber content --- balance. It is desirable to use a continuous cell formulation.

As the above 1,2-polybutadiene,
A vinyl bond content of 70% or more, a crystallinity of 5% or more, and an intrinsic viscosity (η) (30 ° C. in toluene) of dl / g 0.5 or more are used.

As the rubber component, NR, IR, BR, SBR and E having good compatibility with 1,2-polybutadiene.
PDM or the like is preferable.

As the foaming agent, one having a low thermal decomposition temperature (120 to 140 ° C.) among the foaming agents used in the lower layer is used. Specifically, dinitrosopentamethylenetetramine (DPT), azodicarbonamide (ADC
A), azobisisobutyronitrile (AZDN), 4,
4'-oxybisbenzenesulphonyl hydrazide (O
BSH) and the like.

The amount of the foaming agent is 5 to 3 so that the expansion ratio of the soundproof first layer 5a is 3 to 10 times.
Set to 0 PHR. Further, depending on the foaming agent, the thermal decomposition temperature is adjusted by using a foaming auxiliary together.

To the above rubber compound, other auxiliary materials which are compounded in a usual foamed rubber compound, that is, carbon black, an inorganic filler, a processing aid (a softening agent, a tackifier, a plasticizer), an additive are added. A vulcanizing agent, a vulcanization accelerator, a vulcanization accelerating aid, etc. are added in a conventional amount.

(5) The second foaming polymer compound forming the skin layer 15b is not particularly limited as long as it is a closed cell formulation, but the foaming described in the above-mentioned JP-A-62-275743. Rubber compound "polymer, 1,2-
Polybutadiene: 15 to 85 wt%, rubber: balance. It is preferable to use a closed-cell foaming prescription.

In order to obtain a closed-cell foaming formulation, it is sufficient to use a foaming agent having a high thermal decomposition temperature (140 to 160 ° C.) in the foamed rubber compound of the intermediate layer. Specifically, dinitrosopentamethylenetetramine, azodicarbonamide, azobisisobutyronitrile, 4,
4'-oxybisbenzene sulfonyl hydrazide and the like can be mentioned.

The blending amount of the foaming agent is 3 to 20 so that the foaming ratio of the soundproof second layer 5b is 2 to 7 times.
PHR. Further, depending on the foaming agent, the thermal decomposition temperature is adjusted by using a foaming auxiliary together.

In order to improve the soundproofing performance, it is usually preferable that the foaming ratio of each soundproofing layer is such that the soundproofing first layer 5a> the soundproofing second layer 5b.

(6) Formation of vibration damping and soundproofing sheet: (3) above,
(4), (5) Each compound is usually kneaded with a kneader, Banbury mixer, etc., and then roll-extracted or extruded to form a sheet (usually, wall thickness: 0.5 to 3 mm), and three layers are formed. The vibration-damping and sound-proofing sheet of the present invention is formed by laminating and laminating (see FIG. 3).

This sticking work is carried out as separate long products, both are cut into a predetermined size and then laminated, or at the same time when the roll is dispensed or extruded. When the vibration damping and soundproofing sheets of the present invention are stacked, liner paper is interposed between the sheets or dusting is performed.

(7) Construction of vibration-damping and noise-proof sheet The vibration-damping and noise-proof sheet thus obtained is set on the vehicle panel 1 and passed through a drying oven (heating temperature is usually 140 to 160 ° C.). Then, the lower layer 13 is softened by heating and conforms to the surface of the vehicle panel 1 by its own weight, and also the intermediate layer 15a and the skin layer 1
5b foams. Then, the vibration damping and soundproofing structure including the vibration damping layer 3 and the soundproofing layer 5 is formed on the vehicle panel 1 (first.
(See Figure 2). A mat layer (not shown) is usually formed on the upper surface of the soundproof layer 5.

[0031]

Since the vibration damping sheet of the present invention has the above-described structure, when it is applied to a vehicle body panel, it has a soundproofing property in a low frequency region as shown in Examples described later. It is superior to, and has excellent vibration damping performance.

The reason is that the soundproof first layer, which is the intermediate layer, becomes a foam of open cells to increase the sound absorbing property, and the second soundproof layer, which is a skin layer, becomes a foam of closed cells to improve the sound insulation. It is presumed to be because.

[0033]

Examples (1) Each layer material (rubber compound) shown in Table 1 was kneaded with a kneader to obtain 1 mm (1.6 m in the conventional example).
The sheet material for each layer was prepared by extruding to a thickness of m). The sheet materials thus prepared were attached in the combinations shown in Table 2 to form the respective vibration damping and soundproofing sheets of Examples, Comparative Examples and Conventional Examples. Then, the physical properties of each layer and each damping sheet were tested by the following methods. The vibration damping test was carried out on the examples and commercially available bituminous type vibration damping sheets (1.5 mmt).

In the comparative example, the materials of the intermediate layer (soundproofing first layer) and the skin layer (soundproofing second layer) are reversed in the examples, and in the conventional example, the soundproofing layer has an open cell formulation. The one having a one-layer structure formed of the foamed rubber compound (B) (corresponding to the one described in JP-A-62-275743).

(2) Test items Foaming ratio: Place an unfoamed sheet on release paper, 140 ° C.
Heat and foam in a constant temperature bath for 30 minutes. It was determined from the rate of change in thickness before and after foaming at this time.

Specific gravity of foam layer: by water displacement method (JIS K
7222) Soundproofing ... Vibration damping and soundproofing sheet is made of iron plate (380mm x 380mm)
(mm × 0.8 mmt) and then heat-treated at 140 ° C. for 30 minutes to obtain a test piece.

Specifically, the sample is attached to the opening at the boundary between the sound source room and the sound source room, and the sound wave under test is constantly oscillated from the speaker in the sound source room. Each sound pressure level was measured with a 1/3 octave analyzer through a microphone and calculated as the difference between the sound pressure levels in both rooms.

Vibration-damping property: For a test piece (25 mm × 250 mm × 0.8 mmt) prepared in the same manner as the soundproof test, 2
The composite loss coefficient (η _C ) calculated from the measurement results by the mechanical impedin method in each atmosphere of 0, 40, 60, and 80 ° C. was used for the determination.

[0039] (3) Test evaluation: Soundproof of the test results shown in Table 2, the vibration damping soundproof sheet embodiment, compared to that of Comparative Examples and Conventional Example, the low frequency region (500～1000H _Z) It turns out that it has excellent soundproofing performance.

From the vibration damping test results shown in FIG. 4, it can be seen that the vibration damping and soundproofing sheets of the examples are superior in vibration damping performance to the commercially available bituminous damping sheets.

[0041]

[Table 1]

[0042]

[Table 2]

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a construction mode of a vibration damping and soundproofing sheet for a vehicle of the present invention (part I in FIG. 2).

FIG. 2 is an overall schematic cross-sectional view showing a construction mode of the vehicle vibration damping and soundproofing sheet of the present invention.

FIG. 3 is a cross-sectional view showing a pre-construction aspect of the vehicle vibration damping and soundproofing sheet of the present invention.

FIG. 4 is a graph showing a test result of vibration damping performance.

[Explanation of symbols]

 1 vehicle panel, 3 damping layer, 5 soundproof layer, 5a soundproofing first layer, 5b soundproofing second layer, 11 damping soundproofing sheet, 13 lower layer, 15a middle layer, 15b skin layer.

Claims (1)

Claim: What is claimed is: 1. A damper used for forming a vibration-damping and sound-proofing structure comprising a vibration-damping layer attached to a vehicle panel surface and a sound-proofing layer formed on the vibration-damping layer. A vibration-insulating sheet, which has a three-layer structure consisting of a lower layer serving as a damping layer, an intermediate layer serving as a sound-insulating first layer, and a skin layer serving as a second sound-insulating layer, wherein the intermediate layer is continuous. A vibration-damping and sound-insulating sheet for a vehicle, which is formed of a first foaming polymer compound having a cell formulation and wherein the skin layer is formed of a second foaming polymer compound having a closed cell formulation.