JP3067172B2 - Vehicle damping structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to floor panels, dash panels,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight vibration damping structure for a vehicle, which is integrated on a substrate such as a door panel or a ceiling panel, which is easily vibrated, by heat sealing.

[Prior Art] Vehicle floor panels, dash panels, door panels,
A heat-fusible damping material containing asphalt as a main component is often fused to the surface of a vibration base material such as a wheel house.

In recent years, a metal sheet such as a steel plate or an aluminum plate is provided as a constraining material on the upper surface of an asphalt-based vibration damping material, or a thermosetting resin such as an epoxy resin, a diallyl phthalate resin, and an acrylic resin is laminated to form a restrained vibration damping structure. Attempts are also being made to improve the damping ability of the body.

More recently, attempts have been made to improve particularly the damping performance by a method of foaming a damping material containing asphalt as a main component.

[Problems to be Solved by the Invention] However, these vibration damping structures have the following problems. In other words, in a double layer type vibration damping structure in which a vibration base material is damped only with a heat-fusible damping sheet mainly composed of asphalt or the like, it is necessary to increase the thickness in order to improve the damping performance. , Which will increase the vehicle weight.

In addition, although the technology of suppressing the increase in weight by making the asphalt-based vibration damping material foamable has recently started to be used, there is a problem that the improvement of the loss coefficient in a practical range is hardly obtained.

Also, in the case of a sandwich type vibration damping structure in which a steel plate, an aluminum plate, etc. are laminated on the upper surface of an asphalt-based heat-fusible vibration damping sheet, the vibration damping performance of the structure is improved, but the rigidity of the metal as a constraining layer is high. In order to make the plate adhere to the heat-fusible vibration-damping sheet, it is necessary to fix it mechanically to a high-rigidity vibration base material such as a steel plate, or to fix it with screws using bolts or the like. is there. However,
Generally, vehicle floorboards are pressed into irregular shapes for the purpose of imparting rigidity, so it is necessary to form a restraining metal plate in a shape complementary to this, which requires an extra process. There is a problem in that it is not easy to correctly position it at a predetermined position during mounting.

Also, a method of placing an uncured thermosetting resin on a damping material and curing it in a coating drying process to use it as a restraining material,
There is also a method in which a thermoplastic resin having a tackifier resin or the like as a base material is placed on a vibration damping material, thermally fused in a coating and drying step, and used as a restraining material.

The method of using these hard resin materials as the restraint material is certainly effective in improving the loss coefficient and the rigidity, but from the viewpoint of recent reduction of the noise in the vehicle, it is accompanied by a large increase in weight. At present, the improvement range of the loss coefficient and the rigidity when the resin constraining material is used within a practical range is insufficient.

[Means for Solving the Problems] The present invention is an improvement on such a problem, and a vibration damping material sandwiched between a vibration board and a resin restraining material in a vehicle is reduced to 100 parts by weight of butyl rubber. On the other hand, 25 to 75 parts by weight of polybutene having a viscosity of 10 ⁴ to 10 ⁷ cSt at 40 ° C. is added, and the vibration substrate, the vibration damping material, and the resin restraining material are integrally formed by heating. The present invention relates to a vehicle vibration damping structure characterized by being laminated by fusion.

Another object of the present invention is to provide a vehicle panel in which the structure is fused and integrated with a vibration substrate of a vehicle to give an excellent loss coefficient in a range where a weight increase is small.

Further, this type of panel structure for a vehicle needs to be in close contact with the vibrating substrate having irregularities by a heat treatment in a drying process such as painting, and to complete the reaction, foaming, fusion, etc. of each layer. A material that has a small decrease in physical properties even at relatively high temperatures is required as a preferable property,
The structure according to the invention exactly meets these requirements.

 Hereinafter, each constituent layer according to the present invention will be described.

The resin restraining material applied to the present invention is for restraining deformation due to vibration of the vibration damping material and imparting a large loss coefficient to the structure by applying shear deformation to the vibration damping material.

It is desirable that the material provided for such a resin restraining material satisfy the requirements of adhesion (thermal fusion) to the vibration damping material and followability to the uneven vibration substrate by heating, and have as high an elastic modulus as possible.

As a desirable material satisfying such conditions, a rosin-based resin, a terpene-based resin, an aliphatic petroleum resin, an aromatic petroleum resin, an alkylphenol-acetylene resin, a xylene-based resin, a tackifier such as a cumarone-indene-based resin. The thermoplastic resin sheet and the thermosetting plastic sheet to be contained are preferable.

As a thermoplastic resin sheet containing a tackifier resin, there is JP-A-2-197468, and as a thermosetting plastic sheet, a rubber-based base polymer such as butadiene rubber or styrene-butadiene rubber is used. There is.

In particular, a thermoplastic resin sheet containing a tackifier resin has a relatively high elastic modulus in a temperature range of about 0 to 60 ° C., which is a use state of a vehicle, depending on the type and content of the tackifier resin, and is used for coating a vehicle. It becomes a low-viscosity molten material in the temperature range of about 120 to 160 ° C., which is the temperature of the process, and it is easy to design the material so that it can follow complicated uneven shapes. It is easy to handle from the viewpoint of storage stability and the like because it does not contain a reactant.

Although the thickness of the restraint sheet is not particularly limited, a sheet formed on a vehicle floor panel or the like generally has a thickness of about 0.5 to 3 mm.

When it is 0.5 mm or less, it cannot perform an effective function as a restraining material, and when it becomes 3 mmm or more, it deviates from the viewpoint of minimizing the weight increase which is the object of the present invention,
The follow-up adhesion to the uneven vibration substrate due to heating may be deteriorated.

The vibration damping material used in the present invention is obtained by adding at least 10 to 100 parts by weight of polybutene having a viscosity of 10 ⁴ to 10 ⁷ cSt at 40 ° C. to 100 parts by weight of butyl rubber. The butyl rubber used here is not particularly limited, and may have a generally used degree of unsaturation of about 0.5 to 3.0.Also, a halogenated butyl rubber may be used, or a mixture thereof may be used. Of course you can.

The viscosity at 40 ° C. used in the present invention is 10 ⁴ to 10 ⁷ cS.
The polybutene of t imparts a function as a plasticizer to set the temperature dispersion of the loss coefficient in a predetermined temperature range, and at the same time, has an appropriate elasticity and vibration substrate, adhesion to the restraining material, adhesion, etc. Is given. The viscosity of this polybutene at 40 ° C. is 10 ⁴ to 10 ⁷ cSt.
If the viscosity is less than 10 ⁴ cSt, it depends on the amount
The loss coefficient in the high temperature region of not less than ℃ decreases. When the viscosity is 10 ⁷ cSt or more, this is also related to the addition amount,
In the paint baking step, the vibrating substrate having irregularities may not be completely followed, so that not only good damping characteristics cannot be obtained but also the appearance becomes extremely poor.

Furthermore, although this addition amount has a relationship with the viscosity,
It is 10 to 100 parts by weight, preferably 25 to 75 parts by weight. If the amount is less than 10 parts by weight, the loss coefficient at low temperature is reduced, and the substrate may not follow the uneven vibration substrate in the coating baking step.
On the other hand, when the amount is more than 100 parts by weight, the loss coefficient at a high temperature decreases, and the viscosity of the composition becomes too low, so that a good sheet having a uniform thickness cannot be obtained by an ordinary processing method.

Although the thickness of the vibration damping material sheet is not particularly specified, as a sheet formed on a vehicle floor panel or the like,
It is preferable to use it at 3 mm or less. If it is 3 mm or more, it is against the object of the present invention to reduce the weight. There is no lower limit on the thickness. This is because the structure of the present invention has a constrained damping structure, so that its function can be exhibited even if the damping material is thin.

In the vibration damping composition of the present invention, in addition to the above-described composition, improvement in formability and the like is not impaired as long as the function as a vibration damping material is not impaired and there is no problem in forming a floor panel of a vehicle or the like. Other softeners, reinforcing agents such as carbon, inorganic fillers such as calcium carbonate, talc, clay, calcium sulfate, halogen compounds, antimony oxide, zinc borate hydrate, aluminum hydroxide, etc. Flame retardants, heat stabilizers,
A lubricant, an anti-blocking agent, a coloring agent, an ultraviolet inhibitor and the like may be added. Further, in order to reduce the weight, a filler such as a fine hollow body such as a shirasu balloon, a glass balloon, and a foamed stone can be used. Furthermore, in order to improve the durability of the sheet formed on the vibrating substrate, a vulcanizing agent such as sulfur or sulfur donor, a quinoid vulcanizing agent, or a resin vulcanizing agent is used as long as the formability during baking is not impaired. Etc. may be added.

The method of forming the vibration damping material according to the present invention is not particularly limited,
Generally, after kneading with a Banbury mixer or the like, the sheet may be formed with a calendar or the like.

In manufacturing such a structure according to the present invention, the respective layers of the damping material sheet and the restraining material sheet are individually placed on a vibration board of a vehicle, and the vibration board, the vibration damping material, The materials may be alternately fused and at the same time follow the unevenness of the vibrating substrate, or the previously laminated vibration damping material and restraint material may be fused to the vibrating substrate and follow the unevenness in the coating and drying process. You may.

[Effects of the Invention] As described above, the vehicle vibration damping structure according to the present invention is mounted on a vibration substrate such as a vehicle floor panel or dash panel, and heated to heat the vibration substrate, the vibration damping material, and the resin. It is possible to fuse and fix the constraining members and follow the uneven shape of the vibration substrate.

Since the structure obtained in this way is a constrained vibration damping structure, it not only exhibits an excellent vibration damping function over a wide temperature range, but is more weighed than a conventional asphalt-based vibration damping material, It is suitable as a material for reducing vehicle interior noise.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. Parts and percentages in Examples and Comparative Examples are based on weight unless otherwise specified. The materials used for the test and the test method are as follows.

1. Test material Vibration substrate: 0.8 mm thick steel plate Damping material: After kneading the damping material composition in the mixing ratio shown in Table 1 with a kneader, further kneading the roll, and pressing the obtained roll sheet with a press It had a predetermined thickness. In addition, asphalt-based vibration damping materials (trade names: Melsheet,
Nippon Special Paint Co., Ltd.) has a predetermined thickness by pressing.

Restraint: 20 parts of the thermoplastic composition having the compounding ratio shown in Table 2
The mixture was melted and mixed in an autoclave heated to 0 ° C., and the obtained mixture was adjusted to a predetermined thickness by a hot press.

The thermosetting restraining material used was obtained by kneading a thermosetting composition having a compounding ratio shown in Table 3 with a roll and forming a sheet to a predetermined thickness.

2. Vibration suppression performance test Each restraint material layer and vibration suppression sheet layer were 150 x 300 mm each.
Then, a vibration damping structure was prepared by combining with a steel plate having a thickness of 0.8 mm, and the loss coefficient of each structure was measured at 20, 40 and 60 ° C. Lamination of each layer was performed by laminating a vibration damping material and a restraining material on a steel plate, and performing a heat treatment in an oven at 150 ° C. for 30 minutes to fuse the respective layers. The loss coefficient was calculated from the half width of the mechanical impedance from the resonance point, and the 200 Hz loss coefficient was determined by interpolation. The measurement frequency range is 1 to 1000 Hz.

3.Shape follow-up test for uneven plate The above-mentioned asphalt-based damping material and
Cut out to a length of 20 mm and a length of 250 mm, placed on a steel plate with a corrugated shape as shown in Fig. 1 and having a wave height of 7.8 mm so as to be perpendicular to the direction of the wave, and place it in an oven at 150 ° C for 30 minutes. , A heating test was performed to observe the conformability to the uneven shape. Table 4 shows the results. However, the judgment was "〇" for those closely contacted with no gap, and "x" for those with remaining gaps and problems in use.

4. Test Structure and Performance Table 4 shows the configurations and test results of the examples of the present invention, as well as the areal densities of the combined resin restraining material and vibration damping material.

As can be seen from the above test results, the structure of the present invention is:
It excels in vibration damping properties and melts by heating, so it has good followability of irregularities on the vibrating substrate, and it can also reduce the weight, and has characteristics superior to those of conventional vehicle vibration damping structures. is there.

On the other hand, those shown in the comparative examples are in the operating temperature range of 0 to 60 ° C.
In some cases, the loss coefficient is 0.1 or less, or the surface density and unevenness followability are not balanced.

[Brief description of the drawings]

FIGS. 1A and 1B are a front view and a side view, respectively, of a steel plate used for a followability test.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takamitsu Mikuni 1-2-1 Yoko, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Within the Research & Development Center of Nippon Zeon Co., Ltd. 1-2-1 Zeon Corporation Research and Development Center (72) Inventor Masahide Yamamoto 1-10-7 Hatchobori, Chuo-ku, Tokyo Inside Zeon Kasei Corporation (56) References JP-A-60-63147 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16F 15/02 B32B 15/06 B32B 25/08 B62D 25/12

Claims (1)

(57) [Claims] 1. A vibration damping material sandwiched between a vibration substrate and a resin restraining material in a vehicle is a polybutene having a viscosity of 10 ⁴ to 10 ⁷ cSt at 40 ° C. based on 100 parts by weight of butyl rubber.
A vibration damping structure for a vehicle, comprising 5 parts by weight, wherein the vibration substrate, the vibration damping material, and the resin restraining material are integrally fused and laminated by heating.