JP2767862B2 - Method of forming vulcanized rubber layer - Google Patents

Description

The present invention relates to a method for forming a vulcanized rubber layer, and more particularly to a method for forming a vulcanized rubber layer suitable for forming on a surface of a metal gasket.

"Prior art" Conventionally, as a metal gasket, a metal gasket having a vulcanized rubber layer formed on a surface of a metal plate-like material and a non-vulcanized rubber layer formed on the vulcanized rubber layer is known. (Actual opening 61
No. 41960).

Because the non-vulcanized rubber layer has low modulus and hardness,
Filled into minute irregularities on the surface of the cylinder block and cylinder head to improve sealing,
The vulcanized rubber layer formed on the surface of the material has strong adhesion to the material and has relatively large heat resistance and elasticity, so it can withstand high heat and high pressure combustion gas from the combustion chamber. .

[Problems to be Solved by the Invention] However, when manufacturing such a conventional gasket, a vulcanizing agent is first added to and mixed with a non-vulcanized rubber, and then the vulcanization is performed on a plate-shaped material. After forming the non-vulcanized rubber layer to which the agent has been added, the non-vulcanized rubber layer is heated at a predetermined temperature to vulcanize the non-vulcanized rubber layer, and a non-vulcanized rubber layer is formed on the vulcanized rubber layer. Was.

Therefore, the adhesion between the vulcanized rubber layer and the non-vulcanized rubber layer is weak, especially when the cylinder head is made of an aluminum alloy and the thermal expansion coefficients of both are different, such as when the cylinder block is made of cast iron. The rubber layer may be rubbed due to the difference in the coefficient of thermal expansion, and peeling may occur between the vulcanized rubber layer and the non-vulcanized rubber layer, thereby deteriorating the sealing property.

In addition, as the production process, a mixing process of adding and mixing a vulcanizing agent to the non-vulcanized rubber, a cooling process of heating the vulcanized rubber layer to produce a vulcanized product, and then cooling the vulcanized rubber layer, Since a step of forming a non-vulcanized rubber layer on the rubber layer is required, there is a drawback that the step is complicated and requires a long time.

"Means for solving the problem" In view of such circumstances, the present invention forms a vulcanizing agent layer containing a vulcanizing agent on the surface of a material, and then forms a non-vulcanized rubber layer on the vulcanizing agent layer. Then, the non-vulcanized rubber layer is vulcanized to form a vulcanized rubber layer having a lower degree of vulcanization from the surface side of the material to the surface side of the rubber layer.

[Operation] According to the above configuration, each of the above-described steps, which has been conventionally required, is not required, so that the manufacturing process can be simplified and the time can be shortened.

And the vulcanized rubber layer produced by the method of the present invention,
The vulcanized rubber layer is formed as an integral rubber layer having a reduced degree of vulcanization as it goes from the surface side of the material to the surface side of the vulcanized rubber layer, and the rubber on the surface side of the material has a high degree of vulcanization. Adhesion can be achieved with sufficient adhesion. Therefore, according to the vulcanized rubber layer of the method of the present invention, it is possible to secure a sealing property equal to or higher than the conventional one.

"Example" Hereinafter, an example in which the present invention is applied to a gasket of an automobile engine will be described. In FIG. 2, a metal gasket 1 mounted between a cylinder block and a cylinder head and holding a seal between both members is shown. A through hole 1a surrounding the combustion chamber at a required location, a bead portion (not shown) surrounding the through hole 1a, and a bolt hole 1b for mounting are provided. As shown in FIG. 1c, the gasket 1 is composed of a metal plate-shaped material 2 and vulcanized rubber layers 3 formed on both surfaces of the material 2.

FIGS. 1a to 1c show a step of forming the vulcanized rubber layer 3. First, a vulcanizing agent such as an amine, a polyol, or sulfur is uniformly applied to the surface of the metal plate material 2. To form a vulcanizing agent layer 4 (FIG. 1a). At this time, in addition to the vulcanizing agent or before applying the vulcanizing agent, a primer as a vulcanization reaction accelerator and / or a vulcanizing adhesive (for example, silane-based or modified butyral) is applied to the surface of the raw material 2. The vulcanizing agent layer 4 may be applied by coating.

After the vulcanizing agent layer 4 is formed on the surface of the raw material 2, a non-vulcanized rubber layer 5 containing no vulcanizing agent is formed on the vulcanizing agent layer 4 (FIG. 1b). When the material 2, the vulcanizing agent layer 4 and the non-vulcanized rubber layer 5 are heated to a predetermined temperature and thermally vulcanized, the vulcanizing agent of the vulcanizing agent layer 4 is not vulcanized as shown in FIG. 1c. The above-mentioned vulcanized rubber layer 3 is formed on the surface of the plate-shaped material 2 by being combined while diffusing into the vulcanized rubber layer 5.

In the vulcanized rubber layer 3, the amount of the vulcanizing agent added per unit volume decreases from the surface side of the raw material 2 to the surface side of the vulcanized rubber layer 3. Therefore, the degree of vulcanization is large on the surface side of the material 2 with a large amount of addition, and the vulcanized rubber layer 3 is firmly adhered to the surface of the material 2 and has relatively high heat resistance and elasticity. Have.

On the other hand, on the surface side of the vulcanized rubber layer 3 with a small amount of addition, the degree of vulcanization is small and the modulus and tensile strength are low similarly to the non-vulcanized rubber layer. The inside of the part is filled to enhance the sealing property of the part.

[Effects of the Invention] As described above, according to the present invention, the manufacturing process can be simplified and the time can be shortened as compared with the related art, and when applied to a gasket, it is equal to or greater than the related art. The effect that the sealing performance and durability can be ensured can be obtained.

[Brief description of the drawings]

1a to 1c are process diagrams showing one embodiment of the present invention,
FIG. 2 is a plan view of a metal gasket to which the present invention is applied. DESCRIPTION OF SYMBOLS 1 ... Metal gasket, 2 ... Plate material 3 ... Vulcanized rubber layer, 4 ... Vulcanizing agent layer 5 ... Non-vulcanized rubber layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29K 105: 24 B29L 9:00 31:26

Claims (1)

(57) [Claims] 1. After forming a vulcanizing agent layer containing a vulcanizing agent on the surface of a material, a non-vulcanized rubber layer is formed on the vulcanizing agent layer, and the non-vulcanized rubber layer is vulcanized. Forming a vulcanized rubber layer having a lower degree of vulcanization from the surface side of the rubber layer to the surface side of the rubber layer.