JPH0375371B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for attaching an asphalt sheet to a panel surface such as a floor portion of an automobile body.

(Prior art) A method for soundproofing a car body by heat-sealing a heat-adhesive damping material sheet to areas requiring soundproofing was disclosed in Japanese Patent Application Laid-Open No. 1986-
It is disclosed in Publication No. 135373. Further, as a sheet material that is heat-welded to a predetermined location of a vehicle for the purpose of vibration isolation and soundproofing, sheets using asphalt sheets are disclosed in JP-A-60-61376 and JP-A-57-130574. .

Asphalt sheet is made by kneading asphalt, extender pigment, process oil, plasticizer, etc. and then spreading it into a sheet. In general, this type of asphalt sheet is placed in sections during the painting process of an automobile body after the sheet metal process has been completed, and placed on the corresponding parts of the body that have undergone the undercoating process such as electrodeposition coating, and is used in hot air ovens for the next process and subsequent processes, for example. Inside, it is fused to the body by heat in a topcoat baking furnace.

Incidentally, in recent years, the thickness and area of asphalt sheet materials have tended to increase due to rising levels of required values for vibration and noise. However, as the thickness increases, the drop due to heat is insufficient, and the compatibility with the floorboard becomes poor, so it is not always possible to achieve the desired vibration isolation.
If the soundproofing effect cannot be achieved and the area increases, it becomes difficult to transport the asphalt sheet into the body after the sheet metal process has been completed. Therefore, in order to improve thermal adhesion even if the asphalt sheet is thick, the amount of process oil or plasticizer that is a component of the asphalt sheet is increased to make the asphalt sheet flexible, and it is also possible to easily transport the asphalt sheet without completing the ceiling installation. Asphalt sheets are attached during the sheet metal process.

(Problems to be Solved by the Invention) As described above, when an asphalt sheet is pasted in the sheet metal process, the vehicle body will be damaged during the next process of painting, which includes degreasing, surface treatment, electrodeposition painting, and baking. Components such as process oil or plasticizer are extracted from the asphalt sheet surface and dispersed, suspended, or mixed into the electrodeposition paint. As a result, defects such as repellents, dents, and pinholes may occur on the electrodeposited surfaces of the inner and outer panels of the vehicle body.

(Means for solving the problems) The present invention aims to eliminate the above-mentioned drawbacks. The structure of the first invention that meets this objective is that when an asphalt sheet is attached to a panel surface of a vehicle body, at least the entire upper and lower surfaces of the asphalt sheet are covered with a flexible synthetic resin sheet, and then the asphalt sheet is attached to a sheet metal. It is attached to the panel surface of the vehicle body during the process, and then the vehicle body after the sheet metal process is put into the painting process, and the synthetic resin sheet is melted and the asphalt sheet is fused to the panel surface during the baking process after the electrodeposition coating. The main point is to arrive at the meeting.

In addition, a second aspect of the invention in accordance with the above object is that when an asphalt sheet is attached to a panel surface of a vehicle body, at least the asphalt sheet is covered from the top surface to the bottom periphery with a flexible synthetic resin sheet, and then the asphalt sheet is covered with a flexible synthetic resin sheet. The gist is to attach the sheet to the panel surface of the vehicle body during the sheet metal process, and then heat it before the painting process to melt the synthetic resin sheet and fuse the asphalt sheet to the panel surface of the vehicle body. .

(Function) According to the first invention, since the asphalt sheet is carried into the vehicle body during the sheet metal process, it is possible to use an asphalt sheet with a wide area, and the asphalt sheet is covered with a flexible synthetic resin sheet. Therefore, it is possible to prevent process oil and plasticizer from being dispersed or mixed into the electrodeposition paint during the coating process, and there is no risk of adversely affecting the coating.
Therefore, by increasing the amount of process oil and plasticizer, it is possible to use asphalt sheets that are highly flexible despite their large thickness and area. Furthermore, the process is simplified because the synthetic resin sheet can be fused by the heat during the baking process in the painting process without any special heat treatment.

In addition, according to the second invention, the asphalt sheet is carried into the vehicle body during the sheet metal process, heated and fused to the panel surface, and then introduced into the painting process, so that it can be used in the painting process like the vertical side. Asphalt sheets can be reliably attached to areas that cannot be fused using heat.
Moreover, since the asphalt sheet is covered with a synthetic resin sheet as in the first invention, the adverse effects of process oil and plasticizer on the paint surface can be eliminated.

(Example) Examples of the present invention will be described in detail below with reference to the drawings.

In the example shown in FIG. 1, asphalt, extender pigment, process oil, plasticizer, etc. are mixed and kneaded in appropriate amounts, and then the entire surface of the asphalt sheet 1, which is spread into a sheet shape, is made of general-purpose polyethylene that has excellent acid and alkali resistance. Wrap it with sheet 2 and heat seal the periphery to prevent foreign matter such as water from entering. Next, this asphalt sheet 1 is placed on a car body 3 in a sheet metal process, and then the car body 3 is put into a painting process. In this painting process, as shown in FIG. 3, the following treatments are sequentially performed: degreasing, washing with water, surface conditioning, chemical conversion, washing with water, electrodeposition coating, washing with water, and baking. The polyethylene sheet 2 and the asphalt sheet 1 are melted by heat in a hot air oven during a baking process for heating and curing the paint applied by the electrodeposition paint process, and the asphalt sheet 1 is fused to the automobile body 3. Since the surface of the asphalt sheet 1 is covered and sealed with the polyethylene sheet 2, the process oil and plasticizer extracted from the surface of the asphalt sheet during the painting process are dispersed and mixed into the electrodeposition paint during the electrodeposition paint treatment. can be prevented. Therefore, the painted surface was well finished without causing defects such as peeling on the general surface of the body.

In the embodiment shown in FIG. 2, asphalt sheet 1
A general-purpose polypropylene sheet 4 with excellent acid and alkali resistance is wrapped around the area from the upper surface to the lower peripheral edge, and after being attached to the corresponding part 3 of the vehicle body in a sheet metal process, it is heated by means such as high frequency induction heating. The asphalt sheet 1 and the polypropylene sheet 4 were melted and fused to the vehicle body 3. After that, the vehicle body is put into the painting process shown in FIG. Even if the asphalt sheet 1 is fused to the body 3 before the painting process as in this embodiment, the process oil and plasticizer will be dispersed during the painting process and adversely affect the painted surface, as in the first embodiment. I stopped talking. Further, in this embodiment, since the asphalt sheet 1 is heat-fused in advance before starting the painting process, the asphalt sheet 1 can be reliably adhered to the vertical surfaces of the vehicle body.

(Effects of the Invention) According to the first invention, since the asphalt sheet is wrapped in a flexible synthetic resin sheet in advance and is attached during the sheet metal process, the asphalt sheet can be softened by increasing the amount of process oil and plasticizer. However, there is no risk of process oil or plasticizer being dispersed, suspended, or mixed into the electrodeposition paint during the coating process. Therefore, the painted surface has a good finish, and by covering the vehicle body with a thick, large-area asphalt sheet, it is possible to significantly improve the vibration-proofing and sound-proofing effects. In addition, since the heat during the baking process in the painting process is used for fusion, the process is simplified and costs can be reduced. Furthermore, in the past, a mold release agent such as talc was applied to the asphalt sheet to improve workability, but according to the present invention, since the asphalt sheet is wrapped in a synthetic resin sheet, such a mold release agent is not required, improving the working atmosphere. At the same time, release agent particles do not adhere to the painted surface of the body and stain the painted surface.

Further, according to the second invention, as in the first invention, it is possible to eliminate the adverse effects of process oil and plasticizer on the painted surface, and since the asphalt sheet is attached and heated to melting point during the sheet metal process, the painting process can be improved. It can also be reliably attached to vertical surfaces that cannot be fused using heat.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the first invention, FIG. 2 is a sectional view showing an embodiment of the second invention, and FIG. 3 is a painting process diagram. 1... Asphalt sheet, 2, 4... Synthetic resin sheet, 3... Vehicle body.

Claims (1)

[Claims] 1. When attaching an asphalt sheet to a panel surface of a vehicle body, at least the entire upper and lower surfaces of the asphalt sheet are covered with a flexible synthetic resin sheet, and then the asphalt sheet is attached during a sheet metal process. The asphalt sheet is attached to the panel surface of the vehicle body, and then the vehicle body that has undergone the sheet metal process is put into the painting process, and the synthetic resin sheet is melted and the asphalt sheet is fused to the panel surface during the baking process after the electrodeposition coating. Features: How to attach asphalt sheets to vehicles. 2. When attaching the asphalt sheet to the panel surface of the vehicle body, at least the asphalt sheet is covered from the top surface to the bottom periphery with a flexible synthetic resin sheet, and then the asphalt sheet is attached to the panel surface of the vehicle body during the sheet metal process. A method for attaching an asphalt sheet to a vehicle body, the method comprising attaching the asphalt sheet to a surface, and then melting the synthetic resin sheet by heating before a painting process and fusing the asphalt sheet to a panel surface of the vehicle body.