JPH03250085A - Ethylene-propylene rubber-metal composite gasket and its preparation - Google Patents

Abstract

PURPOSE:To prepare a gasket showing a high bonding strength and excellent strength properties and durability by laminating a metallic material with a molded ethylene-propylene rubber through a thermally activated adhesive sheet, and thermally clamping the resulting laminate under pressure to effect adhesion. CONSTITUTION:A process for preparing an ethylene-propylene rubber-metal composite material by laminating and bonding a metallic material (e.g. aluminum plate, copper plate, iron plate, stainless steel plate, or zinc-plated steel plate) with an ethylene-propylene rubber material through an adhesive layer, wherein the adhesive layer comprises a thermally activated adhesive compsn. contg. at least one polyolefin copolymer selected from the group consisting of EVA, EMA, EEA, EAA, acid-graft EVA, acid-graft PE, and acid-graft PP. The obtd. composite material has a high bonding strength and gives a gasket with high strength properties and durability and suitable for use in a valve, etc.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention applies to F, P, etc. used for valves etc.
Regarding the EP rubber/metal composite gasket and its manufacturing method, in detail, it includes an EP rubber/metal composite gasket in which a metal is bonded as a supporting material to an EP rubber with excellent durability, and the above-mentioned gasket with excellent bonding strength. The present invention relates to a method for efficiently producing a composite gas queso].

[Conventional technology]

Various types of valves, such as check valves, aerosol valves, reclosable pressure relief valves, safety valves, and gas release valves for fallen batteries, are manufactured using various rubber materials in the opening/closing part of the flow path where the valve body and valve seat come into contact. A sealed seal member (gasket) is used. These seal members are located at and near the seal portion where the valve body and the valve seat contact, and when the valve is closed, are in close contact with the valve body or the valve seat to prevent gas or liquid from leaking from the seal portion.

The above-mentioned sealing member is required to be made of a flexible rubber material because it needs to come into close contact with the valve body or valve seat. A considerable contact pressure must be applied to the seat, and therefore the sealing member is required to have strength and durability to withstand the above contact pressure. In response to these demands, in the field of sealing members, composite members in which a reinforcing metal material is laminated on an elastic rubber material are widely used, such as EPM, EPDM, and NBR.

Sealing members are used that are made by joining rubber materials such as SBR and CR to metal plates such as AI plates, Cu plates, stainless steel plates, Zn-plated steel plates, and Ni-plated steel plates.

There are various methods for manufacturing such rubber-metal composites. For example, a liquid adhesive such as an epoxy resin or synthetic resin is applied to the surface of the metal plate or vulcanized rubber sheet using a roll coater or a roller coater. There is a method of applying the adhesive using a machine, then bonding a metal plate and a vulcanized rubber sheet, and then pressing with a flat press, roll press, etc. to harden and bond the adhesive.

Incidentally, it is necessary to vulcanize rubber materials in order to obtain a rubber sheet having predetermined physical properties, and the general idea is to use a vulcanized rubber sheet as described above.

On the other hand, a method has also been proposed in which, instead of using a pre-vulcanized rubber sheet, an unvulcanized rubber sheet is used to carry out the vulcanization step and the bonding step at the same time. That is, in this method, a liquid adhesive is applied to the surface of the metal plate by a method such as brush coating, spray coating, or dipping coating, and after drying, unvulcanized rubber is placed on the adhesive coated surface. This is a method of heating and compacting using a flat plate hot press or the like, and at this time, heating and compacting is performed for a predetermined time at a press pressure that allows the unvulcanized rubber to flow and a temperature that allows the unvulcanized rubber to vulcanize. As a result, the rubber material is vulcanized and has a high strength, and also reacts with the adhesive, making it possible to obtain a strong bond between the rubber and the metal plate.

[Problem to be solved by the invention]

However, the former method involves applying a liquid adhesive to a metal plate or rubber sheet and then bonding the two together, which requires a lot of time for preparation work before bonding, which poses the problem of not increasing production efficiency. There is a point. Moreover, the epoxy resin adhesive used here exhibits relatively high adhesive strength among adhesives, but it is a two-flow type and has a high viscosity of 2000 cp or more, and it also has a long pot life. Since the life) is short at 20 to 30 minutes, there is a drawback that workability is extremely poor.

On the other hand, the latter method of vulcanizing and adhering using unvulcanized rubber is
Although this is a method that can firmly bond a rubber material and a metal plate, as described above, it is necessary to apply a liquid adhesive onto the metal plate and dry it, so the bonding preparation work is complicated.

In addition, it is necessary to use a flat plate heat press for vulcanization and adhesion, so if you try to manufacture a large-area composite, you will need to use a large flat plate heat press machine and a large mold, which will increase the equipment cost. In addition to the rising cost, it is difficult to produce long composites using this method.

As described above, there are several problems to be solved in the conventional method, but in addition to these, when using EP rubber as the rubber material of the composite material, the vulcanized EP rubber must be made of natural rubber,
Unlike other rubber materials such as NBR, SBR, and CR, it has a chemically stable molecular structure and has the advantage of being highly durable. However, it has a low affinity for adhesives and adheres strongly to metal plates. The problem is that it is difficult to do so.

The present invention has been made with attention to these circumstances, and is an EP rubber material that is made by firmly bonding highly durable EP rubber and metal materials.
Our first goal is to provide P-based rubber/metal composite gaskets.
71. To develop a method that can efficiently manufacture EP-based rubber/metal composite gaskets using simple equipment and that can also be applied to the production of long EP-based rubber/metal composites. The second purpose is to provide information.

[Means to solve the problem]

The EP rubber/metal composite gasket of the present invention, which has achieved the above object, is an EP rubber/metal composite in which a metal material and an EP rubber material are integrally bonded via an adhesive layer. Adhesive layer is EVA, EMA, EEA, E
The gist is that it consists of a heat-activated adhesive composition containing one or more polyolefin copolymers selected from the group consisting of AA, acid-grafted EVA, acid-grafted PE, and acid-grafted PP, The method of the present invention for manufacturing such an EP rubber/metal composite is that a metal material and a vulcanized EP rubber molded product are laminated via the heat-activated adhesive sheet and bonded by heating and pressing. A gist exists.

[Effect]

Examples of the metal material to be bonded to the EP rubber in the present invention include plate materials such as the above-mentioned AI plate, Cu plate, Fe plate, stainless steel plate, Zn-plated steel plate, and Ni-plated steel plate. On the other hand, EPM is an example of EP rubber.

Examples include EPDM, which is crosslinked in a conventional manner by adding a vulcanizing agent. Although vulcanized EP rubber has excellent weather resistance as described above, it has low affinity with adhesives (and is difficult to firmly bond and integrate with other materials, including metal materials).

The present invention was completed as a result of various studies to eliminate these drawbacks of EP rubber, and the adhesive in the present invention is made of
The main component is one or more compounds selected from ethylene compounds containing ethylene in the skeleton such as , EEA, and EAA, or acid-modified polyolefin compounds such as acid-grafted EVA, acid-grafted PP, etc. It consists of a polyolefin copolymer composition. The polyolefin copolymer, which is the main component of the adhesive, has a molecular structure similar to that of EP rubber, and due to this, it exhibits excellent affinity for EP rubber, so it can be used on the surface of EP rubber. It penetrates well into the minute voids in the material, exerts an anchoring effect, and develops strong adhesive strength. The above polyolefin copolymer has strong polar groups in its side chain portions and graft polymerized acid group portions, so these polar groups exhibit a strong chemical affinity for EP rubber, It is thought that this contributes to the development of good permeability, binding properties, and adhesion.

- The adhesive composition in the strength tree invention can contain a carboxylic acid as one of the components, in which case the carboxylic acid group exhibits good affinity for the metal material and the van der Waals force It also exhibits even stronger adhesion.

In the adhesive composition of the present invention, components other than those mentioned above include rosin, coumaron indene, tackifier such as phenol resin, plasticizer such as phthalate ester, phosphoric ester, chlorinated paraffin, and butyltin type.

It may contain stabilizers such as octyltin-based stabilizers.

Furthermore, the adhesive in the present invention is a heat-activated adhesive, which is in a solid state and does not have adhesive properties at temperatures below 50°C, and melts at 80 to 180°C to increase fluidity and improve adhesive properties. After bonding, the bonded state is solidified by cooling to 50° C. or lower again to form a strong bonded state.

The EP rubber/metal composite gasket according to the present invention is made by integrally bonding EP rubber and a metal material through an adhesive layer as described above. On the other hand, in the method of the present invention for producing the composite gasket, the heat-activated adhesive sheet is interposed between the vulcanized EP rubber and the metal material, and these are heated and pressed in a laminated state to join them together. Since it is possible to use a sheet-shaped heat-activated adhesive, troublesome preparation processes such as adhesive application and drying processes are unnecessary, and the above composite can be manufactured efficiently. can. Moreover, since the adhesive sheet generally has a film shape with a uniform thickness, it is possible to form an adhesive layer with a uniform thickness between the EP rubber and the metal material, resulting in stable quality with less variation in adhesive strength. A complex can be obtained. The reason why EP rubber and metal materials, which have poor adhesion properties, can be firmly bonded using a sheet adhesive is that, as described above, the heat-activated adhesive of the present invention can be used to bond EP rubber and metal materials, which have poor adhesion properties. This is because the heat-activated adhesive exhibits a strong affinity with the adhesive, and the method of the present invention can be carried out by employing the heat-activated adhesive.

In the method of the present invention, there is no particular restriction on the means for heating and pressing the stacked vulcanized EP rubber and metal materials via an adhesive sheet, and for example, a simple means such as a hot roll press may be used. In this case, a roll-shaped adhesive sheet can be used, so that a long composite can be manufactured. However, it is of course possible to use a flat plate heat press or the like.

The conditions for heating and pressing should be selected according to the physical properties of the adhesive described above (0.95°C at a temperature of 80 to 180°C).
The laminate may be heated and pressed by applying a pressing force of 5 to 10 kg/c-, and the heating and pressing operation time is preferably 0.5 to 5 minutes. If the heating temperature is less than 80° C., the adhesive will not melt sufficiently and a good adhesion effect will not be obtained.

On the other hand, it is desirable to avoid heating above 180° C., since this is wasteful from a thermoeconomic perspective and the adhesive tends to undergo thermal decomposition. If the clamping pressure is less than 0.5 kg/ci, sufficient joint strength cannot be obtained due to insufficient clamping pressure.
On the other hand, clamping pressure exceeding 10kg/cIA is due to heating and
Not only is it pointless because it places an excessive burden on the clamping means, but also the device becomes larger in size if a large clamping pressure is to be obtained, leading to an increase in equipment costs. If the heating/pressing time is shorter than 0.5 minutes, the bonding tends to be insufficient, and if it exceeds 5 minutes, the bonding operation can be performed reliably, but the operation time becomes longer and productivity decreases. The thickness of the adhesive sheet used in the method of the present invention is preferably 30 to 250 μm;
If the sheet thickness is less than μm, the sheet thickness is too thin, and the adhesive layer is likely to be damaged during heating and pressing, making it impossible to obtain sufficient adhesive strength. On the other hand, if the thickness exceeds 250 μm, the sheet thickness becomes too large and the strength of the adhesive layer itself decreases, and the bealling strength decreases due to breakage within the adhesive layer.

〔Example〕

Example 1 A rubber material having the composition shown in Table 1 was kneaded using a Banbury mixer or a rubber mixing roll to prepare an unvulcanized EPDM rubber sheet. This unvulcanized rubber sheet was loaded into a mold for making a flat plate, and heated at 170℃ and 180℃ using a flat plate heat press.
Pressed for 10 minutes under heating and pressing conditions of kg/cat,
Vulcanize unvulcanized rubber and measure 100W x 240L
An EPDM vulcanized rubber sheet 3 of X O, 5T+in was produced.

This EPDM vulcanized rubber sheet 3 and 0.55 mm thick Ni
The surfaces of the plated steel plates 1 were each degreased with toluene, and a heat-activated film adhesive (for example, clear tie) with a thickness of 60 μm was prepared between the two by the T-die method 5A-01, thickness 60 μm.
Insert the microfiber (μkan, manufactured by Blockchain Chemical Co., Ltd.) 2, heat and press for 2 minutes at 150°C and 5kg/c1i+ using a flat heat press 4 as shown in Figure 1, and cool at room temperature. An EPDM vulcanized rubber-metal composite gasket as shown in FIG. 2 was manufactured.

18 between the obtained composite gasket and the conventional gasket
Table 2 shows the differences in 0°C beer strength.

In addition, in Conventional Examples 1 and 2, a synthetic rubber adhesive or an epoxy resin adhesive was used to bond the vulcanized EPDM sheet and the metal material.

Marks Table 1 Table 2 Example 2 As shown in Figure 3, the width is 100 fl when wound into a roll.
, a long steel plate 1 with a thickness of 0.3 carbon dioxide, and a roll-shaped heat-activated adhesive film (for example, Cleartite 5R-01, thickness 100 μm, Tanezu Kagaku Kogyo ($1) ) M) 2 and a width of 1200 mm formed with a calendar roll. 9.5 mm thick BP vulcanized rubber sheets (e.g. EPT-t-160, thickness 0.5 Tsuru, manufactured by Kameido Rubber Industry ■) 3 are laminated and heated 30 cm between hot roll presses 5 heated to 120°C. An EP vulcanized rubber-steel composite plate was produced by passing the mixture at a speed of 1/2 min and cooling immediately.

This EP vulcanized rubber-steel plate composite plate was wound up into a roll, and in a separate process was cut into the disk shape shown in FIG. 4 or other shapes using a flat plate press, and used as a gasket.

Example 3 Width 1000. Thickness 0.3n0Al plate 6 and width 1001
m.

Heat-activated film adhesive made of 60 μm thick steel (e.g. Cleartite 5A-01, 60 μm thick, manufactured by Block Chemical Industry Co., Ltd.) 2 and a 110 mm wide, 0.3 m thick E-P vulcanized rubber sheet ( For example, place E l-'T-W-160, thickness 0.31cm, manufactured by Kameido Rubber Industries) 3 in the middle of AIIO2 and place EP vulcanized rubber sheets 3 on both sides as shown in Figure 5. The heat-activated film adhesive 2 was inserted between the sulfur rubber sheets 3 and heated at 150°C using a flat plate heat press.

It was pressed for 2 minutes at 5 kg/cd to create an EP vulcanized rubber/AI board plywood. This was cut into a donut shape as shown in Figure 6 and used as a gasket.

〔Effect of the invention〕

The heat-activated adhesive in this invention is mainly composed of a polyolefin copolymer composition whose molecular structure is similar to that of EP-based vulcanized rubber, and when heated and melted, it forms a bond with the surface of EP-based vulcanized rubber. It exhibits high affinity and sufficiently infiltrates the surface to exhibit strong adhesion. In addition, the heat-activated adhesive is
When a carboxylic acid is contained as one of the components, the carboxylic acid group has a high affinity for the metal material, and therefore exhibits even stronger adhesive force due to van der Waals forces.

Thus, the EP-based rubber/metal composite gasket of the present invention using the above heat-activated adhesive has high bonding strength, and can be used as a gasket for valves, etc., with excellent strength and durability.

In the method for manufacturing an EP rubber/metal composite gasket according to the present invention, a sheet-like adhesive that is non-tacky at room temperature is used, so workability is good and efficiency is high (the above composite gasket can be manufactured). In addition, the use of sheet-shaped adhesives makes it possible to manufacture long plates, making it possible to mass-produce EP-based rubber/metal composite gas get.Furthermore, with sheet-shaped adhesives, it is possible to produce long plates with a uniform thickness. Therefore, a uniform adhesive layer can be formed between the EP rubber and the metal material, and stable adhesive strength can be obtained.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the heating and compacting method using a flat plate hot press, Figure 2.5 is a cross-sectional view showing the structure of a composite board, and Figure 3 is a cross-sectional view showing the method for manufacturing long products using a hot roll press. Explanatory views, FIGS. 4 and 6 are perspective explanatory views showing examples of use of the composite gasket according to the present invention. 1.6- Metal plate, 2- Heat activated adhesive, 3-- El) Vulcanized rubber, 4- Flat plate hot press, 5- Hot roll press. Patent applicant Inaba Rubber Co., Ltd. Sekisui Chemical Co., Ltd. Agent

Claims (2)

[Claims] (1) An EP-based rubber/metal composite in which a metal material and an ethylene-propylene (hereinafter referred to as EP)-based rubber material are bonded together via an adhesive layer, the adhesive layer being
A heat-activated adhesive composition containing one or more polyolefin copolymers selected from the group consisting of VA, EMA, EEA, EAA, acid-grafted EVA, acid-grafted PE, and acid-grafted PP. EP rubber/metal composite gasket. (2) Claiming metal materials and vulcanized EP rubber molded products (1)
Laminated via heat-activated adhesive sheets described in
A method for manufacturing an EP rubber/metal composite gasket, which is characterized by compressing and adhering.