JP2530232B2 - Ethylene propylene rubber / metal composite gasket and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an EP rubber / metal composite gasket used for various valve applications and a method for producing the same, and more particularly, it has excellent durability. The present invention relates to an EP rubber / metal composite gasket in which a metal is bonded and integrated as a support material to an EP rubber, and a method for efficiently manufacturing the above composite gasket having excellent bonding strength.

[Conventional technology]

Various valves such as check valves, aerosol valves, resealable pressure relief valves, safety valves, storage battery gas relief valves, etc. are made using various rubber materials for the flow path opening and closing part where the valve body and valve seat abut. A seal member (gasket) is used. These seal members are in the seal portion where the valve body and the valve seat are in contact with each other and in the vicinity thereof, and closely contact the valve body or the valve seat when the valve is closed to prevent leakage of gas or liquid from the seal portion.

The seal member is required to be formed of a soft rubber material because it is necessary to make a close contact with the valve body or the valve seat, and when it is necessary to reliably maintain the sealed state, A considerable contact pressure must be applied to the valve seat, and therefore the seal member is required to have strength and durability capable of withstanding the above contact pressure. In response to such a demand, in the field of the sealing member, a composite member in which a reinforcing metal material is laminated on a rubber material which is an elastic material is widely used, and for example, rubber such as EPM, EPDM, NBR, SBR, and CR. Material and Al
Sealing members are used that are made by joining metal plates such as plates, Cu plates, stainless steel plates, Zn-plated steel plates, and Ni-plated steel plates.

There are various methods for producing such a rubber / metal composite. For example, a liquid coater such as an epoxy resin or a synthetic resin is coated on the surface of the metal plate or the vulcanized rubber sheet with a roll coater or a trowel. There is a method in which a metal plate and a vulcanized rubber sheet are attached to each other after being applied using, and then pressure is applied by a flat plate press or a roll press to cure and bond the adhesive.

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

On the other hand, a method has also been proposed in which an unvulcanized rubber sheet is used instead of a previously vulcanized rubber sheet to simultaneously perform the vulcanization step and the joining step. 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, dipping coating, etc., and after drying, unvulcanized rubber is placed on the adhesive coated surface and flattened. It is a method of heating and clamping with a board hot press, etc., and at this time, it heats and clamps for a predetermined time at the press pressure at which the unvulcanized rubber can flow and the temperature at which the unvulcanized rubber vulcanizes. As a result, the rubber material is vulcanized to have high strength, and also reacts with the adhesive to obtain a strong joined state between the rubber and the metal plate.

[Problems to be Solved by the Invention]

However, the former method is a method of applying a liquid adhesive to a metal plate or a rubber sheet and then bonding the two together, so that it takes a lot of time for preparatory work before bonding and the production efficiency does not increase. There is a point. Moreover, the epoxy resin-based adhesive used here has a relatively high adhesive strength among the adhesives, but it is a two-component mixed type and has a high viscosity of 2000 cp or more, and has a longer usable time (pot life). ) Is as short as 20 to 30 minutes, so there is a drawback that workability is extremely poor.

On the other hand, the latter method of vulcanizing and adhering using unvulcanized rubber is a method of firmly adhering a rubber material and a metal plate, but as described above, applying a liquid adhesive on the metal plate. Since it needs to be dried, the bonding preparation work is complicated. In addition, since it is necessary to use a flat plate hot press for vulcanization and adhesion, if you try to manufacture a large area composite,
A large flat plate heat press machine and die must be used, and the equipment cost rises, and the long composite is difficult to manufacture by this method.

Thus, there are some points to be solved in the conventional method, in addition to this, when using EP rubber as the rubber material of the composite material, the vulcanized EP rubber is natural rubber, NB
Unlike other rubber materials such as R, SBR, and CR, it has the advantage that it has excellent durability because it has a chemically stable molecular structure, but it has a low affinity for adhesives and firmly adheres to metal plates. There is a problem that it is difficult.

The present invention has been made in view of these circumstances, and is an EP in which a highly durable EP rubber and a metal material are firmly joined.
The first purpose is to provide a rubber / metal composite gasket, and the EP rubber / metal composite gasket can be efficiently manufactured using simple equipment, and a long EP rubber A second object is to provide a method applicable to the production of metal composites.

[Means for solving the problem]

However, 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 joined and integrated via an adhesive layer, Adhesive layer is ethylene vinyl acetate copolymer, ethyl methacrylate copolymer, ethylene ethyl acrylate copolymer, ethylene acrylic acid copolymer, organic acid graft ethylene vinyl acetate copolymer, organic acid graft polyethylene, organic acid graft The main point is that the composition comprises a heat-activatable adhesive composition containing one or more polyolefin-based copolymers selected from the group consisting of polypropylene, and a book for producing such EP-based rubber-metal composites. Inventive method for vulcanization of metallic materials
The gist lies in the fact that EP rubber moldings are laminated via the heat-activatable adhesive sheet, and then heat and pressure are applied for adhesion.

[Action]

Examples of the metal material to be bonded to the EP rubber in the present invention include plate materials such as the above-described Al plate, Cu plate, Fe plate, stainless plate, Zn-plated steel plate and Ni-plated steel plate. On the other hand, as EP rubber, EPM (ethylene / propylene rubber, Ethyle
ne Propylene Rubber), EPDM (Ethylene Propylene Diene Rubber) and the like, which are cross-linked by a conventional method by adding a vulcanizing agent. Although the vulcanized EP rubber has excellent weather resistance as described above, it has a low affinity with adhesives, and it is difficult to firmly bond and integrate it with other materials including metal materials.

The present invention has been completed as a result of various studies to eliminate the drawbacks of the EP rubber, and the adhesive in the present invention has an ethylene vinyl acetate copolymer (Ethylene Vinylacetate copolymer) as shown in the above-mentioned constitution. Hereinafter, referred to as EVA), ethyl methacrylate copolymer (hereinafter, referred to as EMA), ethylene ethyl acrylate copolymer (Ethylene)
Ethylacrylate copolymer, hereinafter referred to as EEA), Ethylene Acryl Acid Copolymer
ic acid copolymer, hereinafter referred to as EAA) or other ethylene compound containing ethylene in the main chain, or organic acid-grafted ethylene vinyl acetate copolymer (hereinafter referred to as acid-grafted EVA), organic acid-grafted polyethylene (hereinafter referred to as Polyolefin copolymer composition containing as a main component one or more compounds selected from acid-modified polyolefin compounds such as acid-grafted PE) and organic acid-grafted polypropylene (hereinafter referred to as acid-grafted PP) It consists of things. As the EMA, a copolymer of ethyl methacrylate and α-olefins such as ethylene can be used. In addition, the content (weight ratio) of ethyl methacrylate, vinyl acetate, ethyl acrylate, and acrylic acid in this EMA or EVA, EEA, EAA
Are each preferably 1 to 45%, and more preferably
15-30% is desirable. Furthermore, as the organic acid used for grafting in the acid-modified polyolefin compound,
Acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, crotonic acid, citraconic acid, citraconic anhydride, etc. can be used, but acrylic acid, methacrylic acid, or maleic anhydride is used. The grafting ratio (weight ratio) is preferably 0.1 to 10%, more preferably about 5%. The polyolefin-based 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.
It penetrates well into the minute voids on the surface of EP rubber, exerts the anchoring effect, and develops a strong adhesive force. Further, since the polyolefin-based copolymer has a strong polar group in the side chain portion and the acid group portion graft-polymerized, these polar groups show a strong chemical affinity for EP rubber, It is considered that it contributes to the development of good penetrability, bondability, and adhesiveness. Therefore, if the adhesive contains at least one of EVA, EMA, EEA, EAA, acid-grafted EVA, acid-grafted PE, and acid-grafted PP, which are polyolefin-based copolymers, as a main component, any compound Even if it contains, it will exhibit a strong adhesive force.

On the other hand, the adhesive composition of the present invention can contain a carboxylic acid such as acrylic acid, methacrylic acid, maleic anhydride, etc. as one of the components, and in this case, the carboxylic acid group has a favorable property to the metal material. It exhibits affinity and exhibits even stronger adhesion to metallic materials due to Van der Waals forces.

The adhesive composition according to the present invention includes, as components other than those described above, tackifiers such as rosin, coumarone indene and phenol resin, phthalic acid esters, phosphoric acid esters, plasticizers such as chlorinated paraffins, butyltin-based and octyltin-based compounds Stabilizers and the like can be included.

Further, the adhesive in the present invention is a heat-activatable adhesive, and does not have adhesiveness in a solid state at 50 ° C. or less, and melts at 80 to 180 ° C. to increase fluidity to improve adhesiveness. After being bonded, it is solidified in the bonded state by cooling again to 50 ° C. or lower after bonding and a strong bonded state is formed.

The EP-based rubber / metal composite gasket according to the present invention is formed by joining and integrating the EP-based rubber and the metal material via the adhesive layer as described above. On the other hand, in the method of the present invention for producing the composite gasket, the heat-activatable adhesive sheet is interposed between a vulcanized EP rubber and a metallic material, and these are heated and pressed in a laminated state to integrally bond them. Since a sheet-shaped heat-activatable adhesive can be used, complicated preparation steps such as an adhesive application step and a drying step are unnecessary, and the above composite can be efficiently produced. it can. Moreover, since the adhesive sheet generally takes the form of a film having a uniform thickness, it is possible to form an adhesive layer having a uniform thickness between the EP rubber and the metal material, and there is little variation in adhesive strength and stable quality. A complex can be obtained. As described above, the EP rubber and the metal material having poor adhesiveness can be firmly bonded using the sheet-like adhesive because the heat-activatable adhesive in the present invention is used for the EP rubber and the metal material as described above. Since it exhibits a strong affinity, the method of the present invention can be carried out by adopting the heat-activatable adhesive.

In the method of the present invention, the means for heating and pressing the vulcanized EP rubber and the metal material laminated via the adhesive sheet is not particularly limited, and simple means such as a hot roll press can be used. In this case, since a roll-shaped adhesive sheet can be used, a long composite can be manufactured. However, it is of course possible to use a flat plate heat press or the like.

The heating / pressing conditions may be selected according to the physical properties of the adhesive described above, and the temperature may range from 0.5 to 10 at a temperature of 80 to 180 ° C.
It suffices to apply a pressing force of kg / cm ² to heat and press the laminated body, and it is desirable that the heating / pressing operation time is 0.5 to 5 minutes. If the heating temperature is lower than 80 ° C, the adhesive will not be sufficiently melted, so that a good adhesive effect cannot be obtained. On the other hand, heating above 180 ° C. is wasteful in terms of heat and economically, and the adhesive is prone to thermal decomposition, so it is desirable to avoid it. If the clamping pressure is less than 0.5 kg / cm ² , sufficient bonding strength cannot be obtained due to insufficient clamping pressure, while the clamping pressure exceeding 10 kg / cm ² will put an excessive burden on the heating and clamping means. Not only is it meaningless, but it also leads to an increase in equipment cost because the apparatus becomes large in size when trying to obtain a large clamping pressure. If the heating / clamping time is shorter than 0.5 minutes, the joining tends to be insufficient, and if it exceeds 5 minutes, the joining operation can be reliably performed, but the operation time becomes long and the productivity is lowered. Further, the thickness of the adhesive sheet used in the method of the present invention is preferably 30 to 250 μm, and if the thickness is less than 30 μm, the adhesive layer is apt to be damaged during heating and pressing because the sheet thickness is too thin. The adhesive strength may not be obtained. On the other hand, if the thickness exceeds 250 μm, the thickness of the sheet becomes too large, and the strength of the adhesive layer itself decreases, and the peeling strength decreases due to breakage in the adhesive layer.

〔Example〕

Example 1 A rubber material having the composition shown in Table 1 was kneaded with a Banbury mixer or a rubber mixing roll to prepare an unvulcanized EPDM rubber sheet. This unvulcanized rubber sheet was loaded into a plate making mold, and pressed with a flat plate hot press at 170 ° C and 180 kg / cm ² for 10 minutes under heating and pressing conditions to vulcanize the unvulcanized rubber. EPDM vulcanized rubber sheet 3 having dimensions of 100 W × 240 L × 0.5 Tmm was manufactured.

The surfaces of the EPDM vulcanized rubber sheet 3 and the 0.55 mm-thick Ni-plated steel sheet 1 were degreased with toluene, and a 60 μm-thick heat-activatable adhesive film (Clearight SA -01 (main component: acrylic acid grafted PE, grafting rate: 5%), thickness 60 μm, Sekisui Chemical Co., Ltd.)
2 and insert it into the flatbed heat press 4 as shown in FIG.
The EPDM vulcanized rubber-metal composite gasket as shown in FIG. 2 was manufactured by heating and pressing for 2 minutes at 5 ° C. and 5 kg / cm ² , and cooling at room temperature. Table 2 shows the difference in 180 ° C peeling strength between the obtained composite gasket and the conventional gasket. Conventional examples 1 and 2 are vulcanized EPD
A synthetic rubber adhesive or an epoxy resin adhesive is used for joining the M sheet and the metal material.

Example 2 As shown in FIG. 3, a long steel plate 1 having a width of 100 mm and a thickness of 0.3 mm wound in a roll shape, and a roll-wound heat-activatable adhesive film having a width of 110 mm and a thickness of 100 μm (for example, Clear tight SB
-01 (main component: EEA), thickness 100μm, Sekisui Chemical Co., Ltd.
2) and width 120 mm, thickness 0.
5 mm EP vulcanized rubber sheet (eg EPT-W-160, thickness 0.5 mm,
An EP vulcanized rubber-steel plate composite was produced by stacking 3 layers of Kameido Rubber Industry Co., Ltd., passing them through a hot roll press 5 heated to 120 ° C. at a speed of 30 cm / min, and immediately cooling.

This EP vulcanized rubber-steel plate composite plate was temporarily wound in a roll shape, cut into a disk shape shown in FIG. 4 or another shape by a flat plate press in a separate step, and used as a gasket.

Example 3 Al plate 6 having a width of 100 mm and a thickness of 0.3 mm and a width of 100 mm and a thickness of 60 μm
Heat-activatable film adhesive (for example, Clear Tight SA-0
1 (main component: acrylic acid grafted PE, grafting ratio: 5
%), Thickness 60 μm, Sekisui Chemical Co., Ltd.) 2 and width 110 m
m, 0.3 mm thick EP vulcanized rubber sheet (eg EPT-W-160, 0.3 mm thick, Kameido Rubber Industry Co., Ltd.) 3 as shown in Fig. 5
l With the plate 6 in the middle, place the EP vulcanized rubber sheets 3 on both sides,
Insert the heat-activatable film adhesive 2 between the plate 6 and the EP vulcanized rubber sheet 3 and press it for 2 minutes under the conditions of 150 ° C and 5kg / cm ² with a flat plate hot press to make the EP vulcanized rubber.・ Al plate composite plate was created. This was cut into a donut shape as shown in FIG. 6 and used as a gasket.

〔The invention's effect〕

The heat-activatable adhesive in the present invention is mainly composed of a polyolefin-based copolymer composition having a molecular structure similar to that of an EP-based vulcanized rubber, and when heated and melted, an EP-based vulcanized rubber surface and It has high affinity and fully infiltrates its surface to exert strong adhesive force. When the carboxylic acid is contained as one of the components in the heat-activatable adhesive, the carboxylic acid group has a high affinity for the metal material, and therefore exhibits a stronger adhesive force by Van der Waals force. Thus, the EP rubber / metal composite gasket of the present invention using the above heat-activatable adhesive has a large bonding strength, and a gasket having excellent strength and durability can be obtained as a gasket for a valve or the like.

In the method for manufacturing the EP-based rubber / metal composite gasket according to the present invention, since the non-tacky sheet-like adhesive is used at room temperature, the workability is good and the composite gasket can be manufactured efficiently. Further, by using the sheet-like adhesive, it becomes possible to manufacture a long plate and mass-produce EP rubber / metal composite gaskets. Further, in the sheet-shaped adhesive, since the adhesive sheet can be formed to have a uniform thickness, a uniform adhesive layer can be formed between the EP rubber and the metal material, and stable adhesive strength can be obtained. You can

[Brief description of drawings]

Fig. 1 is a cross-sectional view showing a heating / pressing method by a flat plate hot press, Figs. 2 and 5 are cross-sectional views showing the structure of a composite plate, and Fig. 3 is a cross-section showing a method for producing a long product by a hot roll press. Illustration,
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 ... EP vulcanized rubber, 4 ... Flat plate hot press, 5 ... Hot roll press.

Claims (2)

(57) [Claims] 1. A metal material and ethylene / propylene (hereinafter,
EP rubber) is an EP-based rubber / metal composite in which a rubber material is bonded and integrated through an adhesive layer, wherein the adhesive layer is an ethylene vinyl acetate copolymer, an ethyl methacrylate copolymer, or ethylene. Contains at least one polyolefin-based copolymer selected from the group consisting of ethyl acrylate copolymer, ethylene acrylic acid copolymer, organic acid-grafted ethylene vinyl acetate copolymer, organic acid-grafted polyethylene, and organic acid-grafted polypropylene An EP-based rubber-metal composite gasket, which is made of a heat-activatable adhesive composition. 2. A metal material and a vulcanized EP rubber molded article are laminated via the heat-activatable adhesive sheet according to claim 1,
A method for manufacturing an EP-based rubber / metal composite gasket, which comprises heating and pressing and adhering.