JPH0418537B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration damping treatment method for, for example, the floor surface of an automobile, and more specifically, the present invention relates to a vibration damping treatment method for, for example, the floor surface of an automobile, and more specifically, to maximize the fused area with the restraining layer regardless of the type of the intermediate layer, and to The present invention relates to a vibration damping processing method with good workability that can realize the peak of excellent damping performance in the vicinity.

Conventionally, sheet-like materials containing bituminous materials and inorganic fillers as main components have been cut into arbitrary shapes and individually heat-sealed to the floor surfaces of automobiles.
These bituminous sheet-like damping materials are due to the temperature sensitivity of the bituminous material, and the damping hardening varies depending on the temperature conditions. It has the characteristic that a peak of damping property appears at , and the damping property gradually decreases at temperatures below and above that temperature. Furthermore, the temperature at which the vibration damping property exhibits a peak increases or decreases and moves toward higher and lower temperatures in proportion to the thickness of the bituminous sheet-like vibration damping material. Therefore, in order to satisfy the recently increasing demand for damping performance that is twice the level of conventional damping performance near 40°C, the thickness of the damping material must be increased by about 3 to 4 times, that is, 8 to 10 m/min. However, an unresolvable contradiction occurred between this and the increasing demand for weight reduction, which made it impossible to put it into practical use.

Therefore, the present applicant provided a restraining layer in the damping material to reduce the thickness of the damping material, thereby reducing the weight and contributing to improving the damping effect at temperatures around 40°C. When integrating, we proposed using foam-type damping material to prevent the fusion area between the restraining layer and the damping material from decreasing due to the distortion of the screws and the restraining steel plate. (Special application 1986-135714,
Patent application 1986-149685).

However, in order to realize excellent workability by eliminating the currently required complicated processes such as the pressing process before the restraining steel plate and the screwing and integrating process, the present inventors have developed a method that can be applied to any type of vibration damping material. We have continued our research to provide a vibration damping treatment method in which a restraining layer is formed by hardening and then curing. As a result, it has been found that the above-mentioned requirements can be conveniently met by a vibration damping treatment in which a sheet containing a specific syndiotactic 1,2-polybutadiene as a main component is used as a restraining layer.

Therefore, the purpose of the present invention is to significantly improve workability, maximize the fusion area between the restraining layer and the damping material regardless of the type of damping material, and provide excellent vibration damping at temperatures around 40°C. The object of the present invention is to provide a vibration damping method that brings out the peak of sex.

Therefore, the gist of the present invention is to use syndiotactic 1,2-polybutadiene.
A restraining layer made of a thermoplastic polymer containing 90 wt% or more, an average molecular weight of 100,000 to 200,000, and a crystallinity of 10 to 40%, and a sheet made of pigment, asphalt, sulfur, or peroxide, hardened by heat. A structure in which a damping material mainly composed of a bituminous substance and an inorganic filler and a vehicle body steel plate are laminated in this order, and the damping material is integrated with the body steel plate and the restraining layer by heat fusion. Vibration damping treatment method for vehicles.

It is in.

The present invention is based on the principle of vibration damping treatment of a sandwich structure consisting of a base material/intermediate layer/restraint layer, and is capable of realizing the vibration effect accompanying the shear action that occurs in the intermediate layer due to vibration.

The bituminous material used in the damping material may be any asphalt, and may be one or a mixture of two or more of straight asphalt, blown asphalt, semi-brown asphalt, and the like.

Generally, bituminous materials alone or mixed asphalt and mixtures thereof with rubber and/or resin components have a softening point of 65 to 115 DEG C. and a penetration of 5 to 100. When the penetration is increased, the softening point of asphalt decreases, resulting in poor workability.In order to overcome this problem, a rubber component and/or a resin component is blended to raise the softening point and improve workability. It is desirable to improve the

As the rubber component to be mixed as necessary, natural rubber, polybutadiene, styrene-butadiene rubber, butyl rubber, neoprene rubber, chloroprene rubber, and other synthetic rubbers may be selected. Further, the use of recycled rubber is preferable from the viewpoint of cost.

As for the resin component to be mixed as necessary like the rubber component, it is preferable to use one or more of petroleum resin, polyethylene, polypropylene, and ethylene-vinyl acetate copolymer.

Inorganic fillers used as other main components of the damping material include any ordinary inorganic filler such as powdered talc, clay, calcium carbonate, etc., fibrous like asbestos, slag wool, and scale-like mica, mica, etc. used alone or in combination as
It may be a mixture of more than one species.

When using a foaming agent, the decomposition temperature must be between 90°C and
A temperature of 160° C. is preferable; however, when producing the damping material, consideration must be given to kneading with the bituminous material and the inorganic filler at a temperature below the decomposition temperature of the blowing agent. Diazoaminobenzole, azoisobutylnitrile, benzol sulfohydrazide, carbamate azide, etc. can be used, but preferably azodicarbonamide, P,P'-oxybenzole sulfohydrazide, benzyl monohydrazole, dinitrosopentamethylenetetramine, etc. be. It is effective to use urea and its derivatives, thermosetting resins, etc. as foaming aids.

The foaming agent is preferably used to foam the damping sheet 1.2 to 2.5 times and adjust the peak temperature of the damping effect.

Furthermore, the water-absorbing composition may be used as an alternative to or together with a foaming agent. When mixing water-absorbing compositions, simply adding water to the water-absorbing composition, which releases volatile gases when heated, will not disperse and uniform foaming cannot be expected. The aim is to obtain a distributed state.

For example, in the production process of vibration damping materials, if a process is used in which heat-molten bituminous material and inorganic filler are mixed in a heated kneader, extruded, and then rolled, the bituminous material alone will be heated and melted at approximately 180°C. Therefore, when the bituminous material and filler have been kneaded to some extent and the temperature of the kneaded material has fallen below 90°C, a blowing agent should be mixed in if necessary. At this time, the initial mixing and the mixing of the blowing agent into the initial mixture may be separate processes, and in the case of a horizontally narrow continuous mixer, the blowing agent may be mixed in the middle of the mixer.

The thermoplastic polymer used as the constraining layer of the present invention is syndiotactic 1,2-polybutadiene.
Must contain 90wt% or more, average molecular weight 10
For example, if the 1,2-polybutadiene content is less than 90 wt%, the rubbery properties will become too large to form a constraining layer, which is inappropriate.

The pigment used in the constraining layer may be calcium carbonate, barium sulfate, talc, asbestos, etc., and if necessary, carbon black.

The type of asphalt may be arbitrary, and straight asphalt, blown asphalt, semi-brown asphalt, etc. are used.

When blending sulfur, it is preferable to mix a vulcanization accelerator, such as thiurams and thiazoles.

As peroxides, dicumyl peroxide,
TBPB, 1,1-bis(t-butylperoxy)
3,3,5-trimethylcyclohexane or the like is used.

In order to impart some flexibility, plasticity may be used as necessary, using DOP, DBP, process oil, etc.

In order to achieve a type of damping treatment in which the damping material is sandwiched between the restraining layer mainly composed of syndiotactic 1,2-polybutadiene and the body steel plate, it is necessary to apply the damping material to the surface of the body steel plate of the vehicle. Laminated,
Next, after laminating the restraint layer, it may be integrated by thermosetting and fusing by baking, or after laminating a damping material on the restraint layer in advance on the body steel plate surface,
A method such as thermal curing and fusion bonding by baking, etc. is used.

That is, for example, without spot welding or seamless welding between the automobile body steel plate surface and the restraining layer,
After being laminated on the surface of the body steel plate via a damping material, it is essential to integrate them by heat softening and fusing by baking or the like.

For thermal softening and fusion integration, it is preferable to bake at 90°C or higher for about 30 minutes, but this value is not particularly limited due to differences in the thickness of the damping material.

Examples are given below to explain embodiments of the present invention in more detail. Naturally, the present invention is not limited to the following examples.

Example 1 Asphalt heated and melted at 170°C (straight asphalt: blown asphalt = 50:50)
After kneading 40 parts by weight, 10 parts by weight of asbestos, and 50 parts by weight of calcium carbonate in a horizontal narrow continuous kneader, 4.
It was made into a damping material with a thickness of m/m.

Syndiotactic 1,2-polybutadiene (JSR manufactured by Japan Synthetic Rubber Co., Ltd.) was used as a restraining layer.
RB) 100 parts by weight, 200 parts by weight of calcium carbonate, 100 parts by weight of barium sulfate, 15 parts by weight of sulfur, 5 parts by weight of a thulum vulcanization accelerator (Noxel TT, manufactured by Ouchi Shinko Kagaku Co., Ltd.), 60 parts by weight of blown asphalt, and A sheet having a thickness of 4 m/m was obtained by kneading 10 parts by weight of TBPB (Perbutyl Z, manufactured by NOF Corporation) as a peroxide at 80°C.

Comparative example 1 A damping material similar to that in Example 1 was obtained.

A steel plate with a thickness of 0.8 m/m was used as the constraining layer.

Example 2 Asphalt heated and melted at 180°C (straight asphalt: blown asphalt = 50:50)
45 parts by weight of asbestos, 10 parts by weight of asbestos, and 45 parts by weight of calcium carbonate were kneaded in a horizontal narrow kneader, and when the temperature of the kneaded product fell to 85°C, 2 parts by weight of azodicarbonamide was added as a blowing agent. The mixture was stirred and dispersed to form a damping material with a thickness of 3 m/m.

A constraining layer similar to that in Example 1 was obtained.

Comparative example 2 A damping material similar to that in Example 2 was obtained.

A steel plate with a thickness of 0.8 m/m was used as the constraining layer.

Results Comparing the workability of the vibration damping treatment methods for Sanderch type vehicles according to Examples 1 and 2 and Comparative Examples 1 and 2, Examples 1 and 2 are similar to those in Comparative Examples 1 and 2. The pressing process and the process of screwing together the vehicle body steel plate and the restraining layer could be omitted, and the workability was extremely excellent.

Claims (1)

[Scope of Claims] 1 Syndiotactic The main component is a thermoplastic polymer containing 90 wt% or more of 1,2-polybutadiene, an average molecular weight of 100,000 to 200,000, and a crystallinity of 10 to 40%, and containing pigments, asphalt, and sulfur. Alternatively, a restraining layer made of a peroxide sheet hardened by heat, a damping material mainly composed of a bituminous substance and an inorganic filler, and a vehicle body steel plate are laminated in this order, and the restraint layer is restrained by heat fusion. A vibration damping treatment method for a vehicle, characterized in that a vibration material is integrated with a body steel plate and a restraint layer. 2. A vibration damping treatment method for a vehicle, characterized in that the sheet composition of the constraining layer according to claim 1 contains a rubber component. 3. A vibration damping treatment method for a vehicle, characterized in that the sheet composition of the constraining layer according to claim 1 contains a resin component. 4. A vibration damping treatment method for a vehicle, characterized in that the sheet composition of the constraining layer according to claim 1 contains a rubber component and a resin component. 5. A vibration damping treatment method for a vehicle, characterized in that the sheet composition of the constraining layer according to claim 1 contains a foaming agent. 6. A vibration damping treatment method for a vehicle, characterized in that the sheet composition of the constraining layer according to claim 1 contains a rubber component and a foaming agent. 7. A vibration damping treatment method for a vehicle, characterized in that the sheet composition of the constraining layer according to claim 1 contains a resin component and a foaming agent. 8. A vibration damping treatment method for a vehicle, characterized in that the sheet composition of the constraining layer according to claim 1 contains a rubber component, a resin component, and a foaming agent.