JPS61263827A - Hole closing method - Google Patents

Abstract

PURPOSE:To make the hole formed for various purposes closable easily and accurately, by stuffing the hole with a seal material, inclusive of a foaming agent, in a state of being plastically deformable so easily by hand, while foaming this into an independent bubble foaming body. CONSTITUTION:The hole 2 formed in a metal plate constituting a car body 1 in automobile manufacture is used at the time of penetrating an electrodeposite solution up to the inside of the car body 1, for example, when electrodeposition coating takes place for the car body 1, and after coating, the electrodeposite solution is discharged outside through hole 2 again. When the said hole 2 is closed, a seal material 3, inclusive of a foaming agent, in a state of being plastically deformable so easily by hand is stuffed in the hole 2, foaming this material and securing an independent bubble foaming body 3a, whereby the hole 2 is closed up. With this constitution, preparations for covers different in size each are no longer required and, what is more, the hole 2 is closable in an easy manner.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hole closing method for closing holes drilled in a vehicle body, a body case of an electrical appliance, a building material, or the like.

] Holes are drilled into the body of the U1 vehicle, including the doors, hood, etc., for various purposes during manufacture. For example, when electrocoating a car body, the electrocoat liquid penetrates into the interior of the car body, so that it can be efficiently discharged after painting, or various types of liquid are applied to the car body for the purpose of improving the drainage performance of the completed car. A hole can be drilled. These holes will be closed by the time the car is completed.

Conventionally, for this purpose, a lid called a grommet made of an elastic material such as rubber was fitted into the hole. However, since holes of various sizes are drilled in the vehicle body, it is necessary to prepare grommets of different sizes to match the holes, making management of these grommets extremely complicated. In addition, dimensional accuracy was required so that the dimensions of the hole and the grommet fitted into it matched. Furthermore, although the grommet is normally fitted into the hole manually by an operator, the grommet becomes hard at low temperatures, such as in winter, and has the disadvantage that it becomes difficult to insert it into the hole.

Instead of a grommet, a method of closing the hole has been adopted in which a pressure-sensitive film coated with an adhesive is pasted over the hole, but in this case as well, pressure-sensitive films of different diameters must be prepared. Furthermore, there is also the drawback that the adhesive strength of the adhesive decreases at low temperatures, making it difficult to apply the film, or that the adhesive strength decreases if dust or the like adheres to the surface to be adhered.

Problems similar to the above-mentioned problems also occur in hole closing methods other than those for vehicle bodies.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hole closing method that eliminates the above-mentioned drawbacks of the conventional method, eliminates the need for preparing lids of different sizes, and allows the holes to be easily closed.

According to the present invention, a sealing material containing a foaming agent that can be easily plastically deformed by hand is packed into a hole, and the sealing material is foamed into a closed-cell foam to close the hole. A hole closure method is proposed.

Cold direct life Two embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a hole 2 drilled in a sheet metal of a car body 1 under manufacture, for example, a floor panel, a door, a hood, etc. Since the hole 2 is drilled in the car body 1 in this way, When performing electrodeposition coating (undercoating), the electrodeposition liquid can be caused to flow through the holes 2 to penetrate into the interior of the vehicle body, and moreover, the electrodeposition liquid can be effectively discharged after painting. The hole 2 can also be used as a drainage hole for draining water from the car body after the car is completed.

After electrocoating, the holes 2 in the vehicle body 1 are closed by the method according to the invention. That is, as shown in FIG.
This is then foamed to obtain a closed-cell foam 3a as shown in FIG. 3, with which the holes 2 are closed. Since the sealing material 3, which can be easily deformed by hand, is stuffed into the hole 2 in this way, the hole 2 can be closed extremely easily without being affected by the outside temperature even if this is done manually. Furthermore, this sealing material 3 contains a foaming agent, which is foam-molded using the hole 2 as a mold, and this functions as a lid. There is no need to prepare a lid made of film, and when the foaming agent is foamed, the sealing material is spread to every corner of the hole, so there is no gap between the foam 1 and the hole 2.
Moreover, since the foam 3a is a closed-cell foam and has neither air permeability nor water permeability, high sealing properties can be obtained.

Any suitable sealing material containing a foaming agent can be used; for example, a suitable amount of a foaming agent is added to a putty or paste-like material of suitable hardness made by blending an appropriate amount of filler with unvulcanized silicone rubber. Added sealing materials can be used advantageously. This sealing material can be used when filling holes.

Since the silicone rubber is in an unvulcanized state, it can be easily deformed by hand and stuffed into the holes.Moreover, if the silicone rubber is vulcanized to obtain the foam 3a, this foam will have appropriate elasticity. It can be taken out from the hole 2 and fitted into the hole 2 again if necessary.

Alternatively, the foaming agent may be foamed by its reaction heat,
In order to foam the sealing material after it is manually packed into the hole 2, it is actually more convenient to foam it by external heating. In this case, the hole 2 may be filled with the sealing material 3 and heated using a special heating means, but for items such as vehicle bodies that require painting other than undercoat, intermediate coat, and topcoat, After the intermediate coating and top coating, the car body is dried in a drying oven or the like, so it is advantageous to use the drying heat to foam the sealing material 3 to simplify the work. For example, if the sealant 3 is stuffed into the holes 2 after the car body has been electrodeposited, either before the intermediate coating is applied or after it dries, but before the top coating is applied, the sealant can be foamed during the drying process after the intermediate coating or top coating. A foam 3a can be obtained. Furthermore, when a sealing material containing unvulcanized silicone rubber is used, it can be vulcanized by dry heat and hardened into a foam having appropriate elasticity.

Next, the results of experiments conducted by the present inventor will be shown.

First, the following materials were used as sealants.

■Unvulcanized silicone rubber (methyl vinyl polysiloxane) 77.5% by weight ■Vulcanization accelerator (2,4-dichlorobenzoyl paraoxide)
2% by weight ■ Filler (silicon) 2
0% by weight 0 Blowing agent (azobisisobutyronitrile (AIBN))
0.5% by weight The above sealing material is packed into the holes of the car body after electrodeposition coating but before intermediate coating, and 1% by weight is applied to the sealing material in a drying oven after intermediate coating.
Drying heat of about 10° C. to 140° C. was applied for 15 minutes or more to foam and cure the product. As a result, an elastic foam was obtained in which the pores were filled without any gaps. The completed foam had excellent sealing properties and could be easily attached and detached from the holes. A similar foam was obtained by filling the holes with the same sealant after drying the intermediate coat but before the top coat and heating it in a top coat drying oven.

Although a specific example in which the present invention is applied to a method of closing holes formed in a vehicle body has been shown above, it is clear that the present invention can be applied as a method of closing holes in any appropriate article other than a vehicle body.

According to the present invention, the hole can be easily closed by a simple operation of lightly stuffing the sealing material into the hole, and even if the size of the hole to be closed is different, it is necessary to prepare many types of lids. There isn't.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a hole in a vehicle body before closing, and FIGS. 2 and 3 are cross-sectional views showing the process of closing the hole.

Claims (3)

[Claims] (1) A hole closing method in which a sealing material containing a foaming agent that can be easily plastically deformed by hand is stuffed into the hole, and the sealing material is foamed into a closed-cell foam to close the hole. (2) The sealing material is a putty-like or paste-like material made by blending unvulcanized silicone rubber with a filler and a foaming agent, and the sealing material stuffed into the hole can be elastically deformed by heating. The method for closing pores according to claim 1, wherein the method is to cure the foam into a closed-cell foam. (3) The hole is formed in the car body, and the sealing material is stuffed into the hole after the car body is electrocoated and before the drying process after intermediate coating or top coating. The pore closing method described in Section.