JPS6129866B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a metal-conductive rubber composite structure, particularly a composite structure with little change in resistance between a metal member and a conductive rubber molded body, and an improved manufacturing method thereof. This is what we provide.

In recent years, structures in which a metal electrode is bonded and integrated with a conductive rubber molded body and a voltage is applied directly to the conductive rubber through the electrode have been developed, for example, for use in electrostatic copying machines for charging or eliminating static electricity. It has come to be widely used as a rubber roll, a conductive rubber blade, a heating roll for fixing, or an electrode body for a low-frequency pulse oscillator for treatment.

Such a composite structure formed by integrating a conductive rubber molded body with a metal electrode is generally manufactured by the following method. That is, (a) After making the surface of the metal member uneven and applying an insulating primer treatment to the concave portions or applying a coupling agent, a conductive rubber molded body is bonded and integrated with this treated surface. (b) Applying a primer or coupling agent in stripes to the joint surface of a metal member or conductive rubber molded body;
(c) A method of forming a fitting opening or through-hole in either the metal member or the conductive rubber molding, and fitting the other member into this. How to integrate.

However, in the composite structure obtained by the above method, a strong insulating coating film is formed between the conductive rubber molded body and the metal member in the areas where the coupling agent or primer is applied. , the uncoated part, i.e.
In areas where the metal member and the conductive rubber molded product are simply in contact, a battery is likely to be formed between them due to the contact between the surface of the metal member and the conductivity imparting agent in the conductive rubber molded product. As a result, corrosion progresses, which is further accelerated by current or changes in the amount of current. Furthermore, even when a battery is not formed, the parts of the surface of the metal parts that are not coated with a coupling agent or primer are easily corroded by water vapor or carbon dioxide gas that passes through the conductive rubber molding, and the metal parts and the conductive rubber The electrical resistance value at the contact surface with the molded body tends to gradually increase. Furthermore, when stress such as compression, bending, or extension force is applied to the composite structure thus obtained, the following phenomenon occurs. In other words, when a compressive force is applied, sliding stress acts on the conductive rubber molded body at the contact surface with the metal member in the area without the coating film, and this sliding stress acts on the conductive rubber molded body at the contact surface with the metal member, as in the case of a conductive rubber roll. If the application is applied repeatedly, the surface of the metal member will be abrasive, and the resulting abrasive powder will accumulate in areas where there is no coating, and this abrasive powder is likely to corrode, and conductive rubber is Cracking is likely to occur due to sliding friction, and therefore, in either case, the electrical resistance value of the contact surface increases. On the other hand, when bending or elongation stress is applied to this, a cavity is created in the part without the coating film, and the resistance value increases significantly. When stress is applied repeatedly or continuously to form an acute angle at the boundary between the molded body and the coating surface that is integrally joined, this stress acts on the joint boundary as if it were a knife edge. This has caused various problems in that it acts as peeling or peeling stress, and is likely to cause peeling or breakage at the bonded portion.

Apart from methods (a) to (c) described above, conventionally, an uncured conductive rubber material containing a conductivity imparting agent is used.
Conductive silicone rubber molded articles are also known in which an organic silane coupling agent or an organic silane peroxide is added to strengthen the chain bonds between the conductivity imparting agents and the bonds with the silicone rubber matrix.
This conductive rubber molded product has excellent bonding properties with metal members, but when molded using a mold, an extremely large amount of separation is formed on the molding surface of the mold. It is necessary to apply a molding agent or to use a mold whose molding surface is coated with fluororesin, and in addition, only molded products of extremely limited shapes can be obtained. In other words, molds treated with a large amount of mold release agent or molds treated with resin inevitably have pinhole-like scratches on the molding surface, so that the conductive rubber molded product may not stick to the edges or protrusions of the molding surface. This is because it is difficult to obtain a molded body that is easily integrated into a solid part and has a desired complex shape. Furthermore, when a large amount of a mold release agent is used to prevent the above-mentioned rubber molded body from being integrated with the mold, there is a drawback that an uncured portion remains on the surface layer of the molded body.
For this reason, there is a method in which a pre-shaped, uncured conductive rubber material is supported on a desired metal member in a steam stream without contacting the mold, and then cured and integrated. The steam ineffectively decomposes the organosilane coupling agent or organosilane peroxide, resulting in poor bonding at the edges of the composite structure thus obtained.
The oxide film layer on the surface of the metal member becomes thicker,
Disadvantages include variations in electrical resistance between the metal member and the conductive rubber molded body, lack of reproducibility, and inability to obtain a desired resistance value.

Note that if hot air heating without steam is used instead of curing and integrating in a steam stream, the heat transfer coefficient is small, so heating must be done with a large temperature difference. It was easy to change in quality and the resistance value was not stable, so it could not be used as a sufficiently reliable electrical component.

The present invention relates to the production of a novel metal-conductive rubber composite structure with stable mechanical and electrical bonding between a metal member and a conductive rubber molded body. The present invention is characterized in that the member and the conductive rubber molded body are integrally bonded via an intermediate conductive rubber layer containing a silane coupling agent or an organic silane peroxide. A method for manufacturing a composite structure is provided, which comprises a metal member,
A conductive rubber layer containing a silane coupling agent or an organic silane peroxide is interposed between the conductive rubber layer and the conductive rubber layer is placed in a compression mold.
It is characterized by being integrated under heat and pressure.

The present invention will be explained in detail below. First, the metal members used in the present invention include iron, copper,
Sheets made of gold, silver, tin, lead, or alloys such as stainless steel, phosphor bronze, solder, and brass;
They are rod-shaped, block-shaped, and irregularly shaped. Conductive rubbers include conventionally known rubbers such as natural rubber, silicone rubber, fluorosilicone rubber, nitrile rubber, butadiene rubber, and ethylene propylene rubber, as well as silver. It is made by dispersing and blending conventionally known conductivity imparting agents such as an atomizer, copper powder, acetylene black, furnace black, and carbon graphite.

In addition, examples of the silane coupling agent added to the intermediate conductive rubber layer in the present invention include tetraethoxysilane, methyltrioxysilane, dimethyldiethoxysilane, alkoxyaminosilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinyltrisoxysilane. (2-methoxyethoxy)silane, 3-methacryloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, Examples include N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane, while organic silane peroxides have the general formula _R2 -Si( ^OOR1 ) _3. , R ₁ is a hydrogen group, methyl group, vinyl group, allyl group, etc., and R ² is a t-butyl group,
Examples include compounds such as a cumyl group.

Next, the composite structure of the present invention, as described above,
A metal member and a conductive rubber molded body are integrated through an intermediate layer made of a conductive rubber containing a silane coupling agent or an organic silane peroxide. Both the molded body and the molded body are integrated into an intermediate conductive rubber layer.

In other words, when looking at metal members and intermediate conductive rubber layers, normally a thin oxide film or oxidized portion is formed on the surface of the metal member immediately in the air even after polishing or surface cleaning. This oxide film or oxidized portion reacts with the silane coupling agent or organic silane peroxide contained in the intermediate conductive rubber layer to form a Si-O-
(Me) bonding occurs and is strongly bonded and integrated. On the other hand, the conductive rubber molded body and the intermediate conductive rubber layer are chemically bonded and integrated according to a known crosslinking mechanism.

In the composite structure of the present invention having such a structure, since the metal member and the intermediate conductive rubber layer are protected by chemical bonding, the metal member and the intermediate conductive rubber layer are protected by chemical bonding. There is no part that is simply in contact with the conductive rubber molded body, and therefore there is no contact between the surface of the metal member and the conductive particles contained in the conductive rubber molded body. There is no problem of battery formation or an increase in the resistance value between the metal part and the conductive rubber molded body due to corrosion in the above-mentioned parts, and furthermore, even when various mechanical stresses are applied to this composite structure, the conductivity between the metal parts and There is no peeling or partial destruction at the joints of the rubber molded bodies, and the bond is mechanically and electrically stable.

In addition, in the composite structure of the present invention, by changing the blending ratio of the conductivity imparting agent to the intermediate conductive rubber layer and the conductive rubber molded body integrated therein, the respective specific resistances can be adjusted. In particular, by setting the specific resistance of the intermediate conductive rubber layer to a value much smaller than that of the conductive rubber molded body, for example, 1/10 or less, it is possible to change the resistivity between the metal member and the conductive rubber. The durability and reliability of the resistance value between the molded body and the molded body can be made higher.

Next, in order to produce a metal-conductive rubber composite according to the method of the present invention, first, a conductive rubber composition A containing a metal member, a silane coupling agent or an organic silane peroxide, and the metal A conductive rubber composition B constituting a molded article to be integrally bonded to a manufactured member and a compression molding mold having a desired molding surface are prepared.

Next, the above-mentioned composition A is dissolved in a solvent and applied to the joining surface of the metal member and dried to a semi-cured state, or after the above-mentioned composition A is formed into a sheet of a predetermined size in an uncured or semi-cured state. , this is placed on the joining surface of a metal member, and then a sheet-like sheet of a predetermined size of the composition B in an uncured or semi-cured state is placed thereon, or, After placing a predetermined measured amount of the mass of the composition B, the mass is placed in the compression mold and heated and pressurized.

Therefore, in the present invention, during the above-mentioned compression molding, the conductive rubber composition B or its molded product and metal member contain a silane coupling agent or an organic silane peroxide even if they come into contact with the molding surface of the mold. Conductive composition A or its molded product should not come into contact with the molding surface of the mold, and even if it does, care should be taken so that only a very small portion of it comes into contact with the molding surface.According to this, after compression molding, When opened, the desired metal-conductive rubber composite structure can be easily and effortlessly removed.

In the method of the present invention, the conductive rubber compositions A and B are charged into a mold for compression molding in a desired shape, for example, a sheet shape, in an uncured or semi-cured state. This is most convenient for manufacturing metal-conductive rubber composite structures on an industrial scale, and the composite structures obtained in this way have extremely high bonding strength between the metal member and the conductive rubber molded body. be taken as a thing.

As explained above, the metal-conductive rubber composite structure of the present invention has an intermediate conductive rubber layer integrated between the metal member and the conductive rubber molded body, so that In addition to having excellent mechanical strength, the state of electrical connection between the metal member and the conductive rubber molded body is stable, and according to the method of the present invention, a silane coupling agent or an organic silane peroxide is contained. Because the intermediate conductive rubber layer is interposed, the metal-conductive rubber composite structure can be manufactured easily and inexpensively on an industrial scale in a compression mold. The practical value is enormous.

Claims (1)

[Scope of Claims] 1. A metal characterized by being formed by integrally bonding a metal member and a conductive rubber molded body through an intermediate conductive rubber layer containing a silane coupling agent or an organic silane peroxide. - Conductive rubber composite structure. 2. A metal characterized in that an intermediate conductive rubber layer containing a silane coupling agent or an organic silane peroxide is interposed between the metal member and the conductive rubber layer, and these are integrally molded under heating. -Method for manufacturing conductive rubber composite structures.