JP5096767B2 - Anti-vibration rubber manufacturing method with bracket and anti-vibration rubber with bracket - Google Patents

Description

  The present invention relates to a method of manufacturing a vibration-proof rubber with metal fittings that has been subjected to cationic electrodeposition coating and a vibration-proof rubber with metal fittings.

  2. Description of the Related Art Conventionally, in vehicles such as automobiles and mechanical equipment, rubber having elastic characteristics is formed in a predetermined shape as a connecting member that is interposed between members of a vibration or shock transmission system and exhibits vibration proofing or buffering properties. Anti-vibration rubbers with metal fittings that are integrally vulcanized and bonded to these metal fittings are widely used.

  In such anti-vibration rubber with metal fittings, in general, the rubber is vulcanized and bonded to the metal fittings and then sprayed with a resin-based paint in order to improve the rust prevention performance or anti-corrosion performance of the metal fittings constituting the metal fittings. By performing (spray) coating treatment or immersion (dip) coating treatment, a resin-based coating film is formed on the surface of the metal fitting. If the paint adheres to the rubber surface due to this coating process, the rubber will be elastically deformed when assembled to an automobile, etc., causing the paint film adhering to the rubber surface to break and tear off, and this peeled-off coating. The film may contaminate the assembly site, or the peeled coating may enter the eyes or mouth of the worker, causing the working environment to deteriorate.Further, the peeled coating may adhere to automobile panels or electrical components. This causes problems such as adverse effects on the product.

  For this reason, usually, prior to the coating process, a masking tape is attached to the rubber surface to perform a masking process on the rubber surface, and then the coating process is performed. By this masking treatment, the adhesion of the paint to the rubber surface can be prevented very effectively, but a step of attaching the masking tape, and further a step of peeling the masking tape after painting are necessary. Work man-hours increased and it was difficult to say that workability was good. In addition, in spray coating and dip coating as described above, it is difficult to control the film thickness of the coating film, and in particular, when using a bonding material that joins or fastens two or more metal members as a metal fitting, It is very difficult to control the film thickness at the joint or fastening part, and there is a problem that a coating film cannot be formed uniformly. Therefore, from these points, there is a strong demand for a technique that has good workability and can easily control the film thickness.

  By the way, as a method of obtaining a vibration-proof rubber with a metal fitting obtained by applying a resin-based paint to the surface of the metal fitting, various methods have been proposed, and one of them is as follows. Patent Document 1 discloses a technique for forming a corrosion-resistant vibration-proof element by vulcanizing and bonding rubber to a metal fitting electrodeposited with an epoxy-based cationic electrodeposition paint. Discloses a technique for obtaining a vibration-proof rubber with a metal fitting by vulcanizing and bonding the rubber to the metal-coated metal electrodeposited metal fitting. According to such cationic electrodeposition coating, even if the shape of the metal fitting is complicated, it is possible to control the film thickness uniformly, and excellent antirust properties can be imparted to the metal fitting. In the described method, since the cationic electrodeposition coating is performed before the rubber is vulcanized and bonded, a mold structure that does not cause rubber burrs is required from the viewpoint of product shape, productivity, etc. At the time of rubber vulcanization adhesion, the metal fitting will be heated in contact with the rubber molding die, so that the electrodeposition coating film peels off at the contact portion with the molding die, etc. There was a problem that the coating film was easily damaged.

  On the other hand, Patent Document 3 discloses a method for producing a corrosion-resistant vibration-proof rubber, in which a rubber is vulcanized and bonded to a metal fitting, followed by cationic electrodeposition coating, and the coating film is cured at a low temperature of 150 ° C. or lower, and a metal However, in a vibration-proof rubber composed of a plurality of parts through rubber, a method for producing a corrosion-resistant vibration-proof rubber by conducting a conductive treatment between metal parts prior to electrodeposition coating has been clarified. However, in this document, no examination is made on the adhesion of the cationic electrodeposition paint to the rubber surface and the problems caused by the adhesion. It has been clarified that carbon black and graphite are blended.

  Under such circumstances, the present inventors performed cationic electrodeposition coating on the integrally vulcanized product after vulcanization adhesion. As a result, not only the surface of the highly conductive metal fitting but also the conductive material compared to the metal fitting. It was revealed that an electrodeposition coating film was also formed on the rubber surface with extremely low properties. Therefore, in the case of performing cationic electrodeposition coating, as in the case of spray coating or dip coating as described above, masking treatment is necessary, and it has been found that workability is not good in mass production. It was.

Japanese Patent Publication No.59-51905 JP-A-62-24042 Japanese Patent Publication No. 4-55589

  Here, the present invention has been made against the background of such circumstances, and the problem to be solved is that the workability is good and the electrodeposition coating film is not formed on the rubber surface. To provide a method for producing a vibration-proof rubber with a metal fitting having excellent properties, and to provide a vibration-proof rubber with a metal fitting having excellent rust resistance without forming an electrodeposition coating on the rubber surface. is there.

And as a result of intensive studies on the adhesion of the cationic electrodeposition paint to the rubber surface by the present inventors, the rubber constituting the anti-vibration rubber with metal fittings may or may not have paint adhesion. As a result of further investigation, the cationic electrodeposition paint does not adhere to the rubber surface in the integrally vulcanized product of the rubber elastic body and the metal fitting having a surface resistance value of 1 × 10 ⁶ Ω or more. The present inventors have found that the above problems can be solved and have completed the present invention.

That is, according to the present invention, an unvulcanized rubber obtained by blending 40 to 70 parts by weight of carbon black having a nitrogen adsorption specific surface area of 70 m ² / g or less with 100 parts by weight of an unvulcanized rubber material is integrated with a metal fitting. to tighten dressing vulcanization, on the gold member, the surface resistance value by forming the rubber elastic body is 1 × 10 ⁶ Ω or more, integral after the vulcanized product, cationic electrodeposition in accordance integrally vulcanized product paint By forming the electrodeposited coating film only on the metal fitting surface of the integrally vulcanized product without forming an electrodeposited coating film on the surface of the rubber elastic body of the integrally vulcanized product. The gist of the manufacturing method of the vibration-proof rubber with metal fitting is as follows.

The present invention also relates to a vibration-proof rubber with a metal fitting obtained by subjecting an integrally vulcanized product of a rubber elastic body and a metal fitting to cationic electrodeposition coating, wherein the rubber elastic body is 100 weight of an unvulcanized rubber material. 1 × 10 ⁶ Ω or more surface formed by vulcanization adhesion using 40 to 70 parts by weight of carbon black having a nitrogen adsorption specific surface area of 70 m ² / g or less. together they have a resistance value, without the electrodeposition coating film is formed on the surface of the rubber elastic body, only on the surface of the fitting, by an electrodeposited coating the cationic electrodeposition coating is formed The anti-vibration rubber with metal fittings characterized by this is also the gist of the invention.

Thus, in the method for manufacturing a vibration-proof rubber with a metal fitting according to the present invention, a rubber elastic body having a surface resistance value of 1 × 10 ⁶ Ω or more is formed, and thus the rubber elastic body and the metal fitting are used. Even if the monolithic vulcanized product is subjected to cationic electrodeposition coating, it is advantageously prevented that a coating film is formed on the rubber surface, and only the metal surface of the monolithic vulcanized product is coated. Therefore, even when rubber is elastically deformed during assembly to automobiles, etc., the coating film will not crack and peel off, and thus the peeled coating film will contaminate the assembly site. There is nothing to provoke. Therefore, according to the method of the present invention, it is not necessary to mask the rubber surface prior to the cationic electrodeposition coating, thereby greatly improving the workability of the coating process.

  In addition, according to the method of the present invention, when cationic electrodeposition coating is applied to an integrally vulcanized product after vulcanization adhesion, before applying vulcanization adhesion, cationic electrodeposition coating is applied to a metal fitting. In contrast, the electrodeposition coating film does not peel off at the contact portion with the molding die, and an advantage that excellent rust prevention (corrosion resistance) is imparted can be enjoyed.

Further, in the vibration-proof rubber with metal fittings according to the present invention, an electrodeposition coating film is formed on the rubber surface because the rubber elastic body has a surface resistance value of 1 × 10 ⁶ Ω or more. Therefore, even when the rubber is elastically deformed during assembly to an automobile or the like, the coating film will not be tattered and peeled off. In addition, since the electrodeposition coating by cationic electrodeposition coating is formed on the surface of the metal fitting, the coating thickness is made uniform compared to coating by spray coating or immersion coating, providing excellent protection. Rust is imparted.

By the way, the method of the present invention as described above is advantageously applied to the production of a vibration-proof rubber 10 with a metal fitting as shown in FIGS. 1 and 2, for example. Here, in FIG. 1 and FIG. 2, the mount stopper as the vibration isolating rubber 10 with the metal fitting is schematically shown in the plan view and the longitudinal sectional view. The substantially annular rubber elastic body 16 provided with four convex portions 14 extending in the circumferential direction with a predetermined interval on one surface of the substantially annular plate-shaped metal fitting 12 is integrally vulcanized. Bonded and configured. The rubber elastic body 16 has a surface resistance value of 1 × 10 ⁶ Ω, while the surface 13 of the metal fitting 12 other than the portion bonded to the rubber elastic body 16 is enlarged in FIG. As shown, the electrodeposition coating film 18 made of a resin coating film is formed in a substantially uniform thickness. In FIG. 2, in order to facilitate understanding of the electrodeposition coating film 18 formed on the metal surface 13, the electrodeposition coating film 18 is exaggerated and shown with an extremely thick thickness. Should be understood.

  When manufacturing such a vibration-proof rubber 10 with a metal fitting according to the present invention, first, the vibration-proof rubber composition, which is an unvulcanized rubber, is integrally vulcanized and bonded to the metal fitting 12 to obtain a rubber. An integral vulcanized product of the elastic body 16 and the metal fitting 12 is formed.

At this time, in the present invention, the anti-vibration rubber composition (unvulcanized rubber) for forming the rubber elastic body 16 is an anti-vibration composition having an extremely low conductivity that has a surface resistance of 1 × 10 ⁶ Ω or more after vulcanization. Since a vibration rubber composition is used, adhesion of the cationic electrodeposition paint to the rubber elastic body 16 can be advantageously prevented.

  More specifically, such an anti-vibration rubber composition is mainly composed of an unvulcanized rubber material. Examples of the rubber material include natural rubber (NR) and isoprene rubber (IR). ), Butadiene rubber (BR), styrene butadiene rubber (SBR), ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), butyl rubber (IIR), silicone rubber (Q), acrylic rubber (ACM), etc. The rubber material conventionally used for an anti-vibration rubber | gum can be mentioned, One of these can be used individually or can be used by blending 2 or more types. Among these, rubber materials containing NR as an essential component, such as a blend of NR, NR and BR, or a blend of NR and SBR, are more preferably employed, thereby further improving the prevention. The vibration characteristics will be exhibited. These rubber materials may be blended with other rubber materials or the like as long as the object of the present invention is not impaired.

  For rubber materials such as those mentioned above, various known rubber compounding agents such as reinforcing agents, vulcanizing agents, vulcanization accelerators, vulcanization accelerating aids, softeners, anti-aging agents, etc. Thus, an anti-vibration rubber composition capable of realizing a desired anti-vibration property is prepared by blending appropriately.

Here, as the reinforcing agent blended for imparting hardness and strength, carbon black is usually used. However, as is well known, such carbon black has conductivity. Yes. For this reason, as the blending amount increases, the surface resistance value of the rubber elastic body 16 is lowered, and the target surface resistance value (1 × 10 ⁶ Ω or more) cannot be realized. Similarly, various grades of carbon black such as FT, GPF, SRF, FEF, and HAF are commercially available. Generally, the larger the specific surface area (the smaller the particle size), the more rubber There is a tendency to reduce the surface resistance value of the elastic body 16.

Therefore, in the present invention, the nitrogen adsorption specific surface area is measured according to JIS K 6217-2 is 70m ² / g or less, more carbon black preferably becomes 10 to 60 m ² / g is, the rubber material 100 wt It is desirable to be used at a blending ratio of 40 to 70 parts by weight with respect to parts, and at least one of various carbon blacks is used alone or in combination of two or more so as to satisfy these ranges. It is used. This is because when the specific surface area of carbon black exceeds the above range, the surface resistance value of the rubber elastic body 16 should be 1 × 10 ⁶ Ω or more unless the blending amount of the carbon black is less than the lower limit of the blending range. If the blending amount of the carbon black is less than the above range, the effects of blending the carbon black cannot be enjoyed, for example, the product physical properties such as hardness and strength are reduced. This is because the processability of the vibration-proof rubber composition may be deteriorated. Further, when the blending amount of carbon black exceeds the above range, the surface resistance value of the rubber elastic body 16 is less than 1 × 10 ⁶ Ω, and a coating film is formed on the surface 17 of the rubber elastic body 16 at the time of cationic coating described later. It is because there is a risk of being.

In the present invention, in particular, among the various grades of carbon black described above, two or more different grades may be used in combination. By doing so, various characteristics according to each carbon black are imparted. As a result, it is possible to achieve both a more excellent anti-vibration characteristic and a high electrical resistance. When two or more different types of carbon black are used in combination, the total blending amount of the blended product with the specific surface area (JIS K 6217-2) and the blending amount of each carbon black is the above range, respectively. It is desirable that the surface resistance value of the rubber elastic body 16 be advantageously 1 × 10 ⁶ Ω or more.

  On the other hand, as the vulcanizing agent, a conventionally known vulcanizing agent corresponding to the rubber material is used in an appropriate amount corresponding to the amount of the rubber material used. In particular, in order to use a diene rubber material such as natural rubber as described above, generally a sulfur vulcanizing agent such as sulfur is preferably used.

  Furthermore, various vulcanization accelerators and vulcanization assistants may be appropriately blended in the vibration-proof rubber composition, and examples of the vulcanization accelerator include N-oxydiethylene-2-benzothiazole sulfate. Sulfenamides such as phenamide (OBS); dithiocarbamates such as zinc dimethyldithiocarbamate (ZnMDC); thiurams such as tetrabutylthiuram disulfide (TBTD); and vulcanization accelerators Examples thereof include, but are not limited to, zinc oxide and stearic acid.

  In addition, the anti-vibration rubber composition has a 2,2,4-trimethyl-1,2-dihydroquinoline multimer, N- (1,3-dimethylbutyl), in order to improve physical properties such as heat resistance. It is desirable to add an anti-aging agent such as —N′-phenyl-p-phenylenediamine, etc. in an appropriate amount so that even if the electrodeposition coating film is baked, the rubber will deteriorate. This can be advantageously prevented. In addition, a softening agent such as naphthenic oil, paraffinic oil, and aroma oil can be added to the vibration-proof rubber composition in an appropriate amount so as to improve processability.

  Thus, the anti-vibration rubber composition containing various components as described above can be prepared by a conventionally known method. For example, using a known kneading apparatus, an unvulcanized rubber material is contained in the apparatus. And various compounding agents such as carbon black can be prepared by introducing them simultaneously or in any order and kneading them uniformly.

  On the other hand, examples of the metal fitting 12 to which the rubber composition thus prepared is vulcanized and bonded include, for example, rolled materials made of materials such as iron, steel, aluminum, and aluminum alloys, and plastic processed materials such as forged materials. be able to. Further, the surface 13 of the metal fitting 12 may be subjected to a chemical conversion film treatment or a plating treatment.

Then, by integrally vulcanizing and adhering the vibration isolating rubber composition as described above to the metal fitting 12, the rubber elastic body 16 having a surface resistance value of 1 × 10 ⁶ Ω or more and the metal fitting 12 are integrally vulcanized. You can get the goods. More specifically, after applying an appropriate vulcanized adhesive such as a chlorinated rubber adhesive or a primer to a part or all of the adhesion part of the metal fitting 12 to the rubber elastic body 16 as in the prior art, An integral vulcanized product is produced by vulcanizing and bonding rubber to the metal fitting 12. In this vulcanization bonding operation, various conventionally known methods can be appropriately employed. For example, first, a vulcanization adhesive is applied to the bonding surface of the metal fitting 12, and then a molding die is used. , at a predetermined position in the mold cavity, after allowed placing member 12, such molding die vibration damping rubber composition into the cavity by injection, then, it is allowed to heat at a predetermined temperature, the unvulcanized rubber vulcanizing A method of bonding the metal fitting 12 and the rubber elastic body 16 at the same time as the rubber elastic body 16 is formed by performing sulfur molding is adopted.

In the integrally vulcanized product thus produced, the rubber elastic body 16 constituting the integrated vulcanized product has a surface resistance value of 1 × 10 ⁶ Ω or more. And after that, by carrying out a cationic electrodeposition coating operation using a cationic electrodeposition coating on such an integrally vulcanized product of the rubber elastic body 16 and the metal fitting 12, it is shown enlarged in FIG. As described above, the electrodeposited coating film 18 having the performance of preventing the occurrence of rust or corrosion is formed on the surface 13 of the metal fitting 12 other than the part to be bonded to the rubber elastic body 16, and the vibration-proof rubber with metal fitting 10 is manufactured. It is done.

  Specifically, the cationic electrodeposition coating is performed by immersing the integrated vulcanized product after vulcanization adhesion in a treatment bath made of a predetermined cationic electrodeposition coating using a conventional electrodeposition apparatus. This is carried out in accordance with a general procedure in which a direct current is applied with a sulfur product as a cathode. At this time, the applied voltage, energization time, bath temperature, etc. employed are appropriately set according to the pole ratio (area ratio between the anode and the cathode), the type of cationic electrodeposition paint, etc. About 50 to 500 V, preferably about 150 to 300 V, energization time is about 2 to 5 minutes, and bath temperature is about 10 to 45 ° C, preferably about 30 to 40 ° C.

Thereafter, the integrally vulcanized product having the cationic electrodeposition paint attached to the surface 13 of the metal fitting 12 is taken out of the treatment bath, washed with water, and then subjected to a predetermined baking treatment, whereby only the surface 13 of the metal fitting 12 is applied. The anti-vibration rubber 10 with metal fittings on which the electrodeposition coating film is formed is manufactured. In this case, as the baking treatment temperature, a temperature of 180 ° C. or lower, preferably 120 to 160 ° C., is adopted from the viewpoint of preventing the deterioration of the rubber, and the treatment time is about 10 to 30 minutes.

  The type of cationic electrodeposition coating used in the above cationic electrodeposition coating operation is not particularly limited, and generally has an advantage in rust prevention performance or anticorrosion performance required for the vibration isolating rubber 10 with metal fittings. Those that can be realized are selected and used as appropriate. As such a cationic electrodeposition coating, generally, a water-based solvent, a cationic binder component, a pigment component (for example, a color pigment, an extender pigment, a rust preventive pigment), and an additive (for example, , Rust preventive, curing catalyst, neutralizing acid, etc.) are used. In the present invention, among them, a modified epoxy resin is used as a main component as a binder component. Those using blocked isocyanate as a curing agent (crosslinking agent) can be suitably employed because they exhibit excellent rust prevention properties.

  And, by the coating operation using such a cationic electrodeposition paint, the electrodeposition coating film 18 is formed only on the surface 13 of the metal fitting 12, and its thickness is generally 15-30 μm. Thickness of about.

Thus, in the manufacturing method of the vibration isolating rubber 10 with the metal fitting according to the present invention, an operation of vulcanizing and bonding the unvulcanized rubber to the metal fitting 12 is performed, and the surface resistance value is 1 × 10 ⁶ Ω. Since an integral vulcanized product of a certain rubber elastic body 16 and the metal fitting 12 is formed, and then this integral vulcanized product is subjected to cationic electrodeposition coating, the surface 17 of the rubber elastic body 16 is electrically charged. An electrodeposition coating film 18 having a substantially uniform thickness is formed only on the surface 13 of the metal fitting 12 without forming a coating film, and rust prevention is imparted. For this reason, it is not necessary to perform the masking process on the rubber surface 17 prior to the cationic electrodeposition coating, and workability is greatly improved. In addition, since the cationic electrodeposition coating is performed after the vulcanization adhesion, unlike the case where the cationic electrodeposition coating is applied to the metal fitting prior to the vulcanization adhesion operation, it is also advantageous that the electrodeposition coating 18 is peeled off. Thus, excellent rust prevention can be ensured over a long period of time.

Further, in the vibration-proof rubber with bracket 10 manufactured as described above, the surface resistance value of the rubber elastic body 16 is set to 1 × 10 ⁶ Ω or more, and an electrodeposition coating film is formed on the rubber surface 17. Since this is advantageously prevented, even when the rubber is elastically deformed during assembly to an automobile or the like, the coating does not peel off. Moreover, since the electrodeposition coating film 18 by the cationic electrodeposition coating is formed on the metal surface 13, the coating film is formed with a uniform thickness as compared with spray coating or immersion coating.

  The exemplary embodiments of the present invention have been described in detail above. However, the embodiments are merely examples, and the present invention is limited in any way by specific descriptions according to such embodiments. It should be understood that it is not interpreted.

  For example, in the above example, as the vibration-proof rubber 10 with a metal fitting, a method for manufacturing a mount stopper constituted by a substantially ring-shaped metal fitting 12 and a substantially annular rubber elastic body 16 has been exemplified. The method can be applied to any anti-vibration rubber with metal fittings in which a rubber elastic body is integrally vulcanized and bonded to the metal fittings. Needless to say, it is not limited to vibration-proof rubber. For example, a metal fitting having a shape in which a rubber elastic body is interposed between two metal fittings arranged to face each other. The present invention can also be advantageously applied to the manufacture of attached anti-vibration rubber.

  Further, in the above example, after forming the integrally vulcanized product of the rubber elastic body 16 and the metal fitting 12, the integral vulcanized product was subjected to cationic electrodeposition coating, but prior to the cationic electrodeposition coating, It is also possible to carry out a chemical conversion film treatment such as chromate treatment or phosphoric acid treatment on the integrally vulcanized product by a conventionally known method. By performing this chemical conversion film treatment, it is further improved. Rust prevention can be imparted to the metal fitting 2.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art. It goes without saying that any one of them falls within the scope of the present invention without departing from the spirit of the present invention.

  Several examples of the present invention will be shown below to clarify the present invention more specifically. However, the present invention is not limited by the description of such examples.

-Preparation of anti-vibration rubber composition (unvulcanized rubber)-
First, natural rubber was prepared as a rubber material, while five types of carbon blacks A to E of various grades shown in Table 1 below were prepared as reinforcing agents. Moreover, anti-aging agent 6C (made by Seiko Chemical Co., Ltd .: Ozonon 6C) and anti-aging agent RD (made by Seiko Chemical Co., Ltd .: non-flex RD) are used as anti-aging agents, and stearic acid (Kao) is used as an accelerator for vulcanization. Made by Co., Ltd .: Lunac S30) and zinc oxide (made by Sakai Chemical Industry Co., Ltd .: 1 type of zinc oxide), naphthenic oil (made by Idemitsu Kosan Co., Ltd .: Diana Process NM280) as a softening agent, sulfur ( Tsurumi Chemical Co., Ltd .: Sulfax 200S) is used as a vulcanization accelerator, vulcanization accelerator MSA (Ouchi Shinsei Chemical Co., Ltd .: Noxeller MSA) and vulcanization accelerator TBT (Ouchi Shinsei Chemical Co., Ltd.). : Noxeller TBT).

  And according to the various compounding composition shown in the following Table 2, natural rubber, reinforcing agent, anti-aging agent, vulcanization accelerating aid and softening agent were charged into a Banbury mixer and kneaded. Anti-vibration rubber compositions according to Examples 1 to 6 and Comparative Examples 1 and 2 were prepared by adding vulcanization accelerator and vulcanization accelerator, kneading in a roll machine, and mixing uniformly.

-Evaluation of non-adhesiveness of cationic electrodeposition coatings-
And the test piece for the electrodeposition coating which concerns on Examples 1-6 and Comparative Examples 1 and 2 was produced using the vibration-proof rubber composition obtained above. Specifically, first, as a metal fitting, a rectangular plate-shaped rolled steel material (SS400 material, 60 mm × 25 mm × 2.3 mm) as shown in FIG. 3A is used, and one surface (rubber bonding surface) of this metal fitting is used. ) Is coated with a chlorinated rubber adhesive (Lord Co., Ltd .: Chemlock 205) as a primer, dried with hot air, and then further coated with another chlorinated rubber adhesive. An agent (available from Lord Corporation: Chemlock 6108) was overcoated and dried with hot air. Next, the metal fitting is placed in the molding cavity of the mold so that the rubber bonding surface is on top, and then the anti-vibration rubber composition (unvulcanized rubber) molded into a strip shape is placed thereon. Then, by press vulcanization at 150 ° C. for 20 minutes, the unvulcanized rubber is vulcanized to form a rubber elastic body, and the metal fitting and the rubber elastic body are bonded together, as shown in FIG. A rectangular plate-shaped test piece (125 mm × 25 mm × 7.5 mm) as shown was produced. Then, prior to the cationic electrodeposition coating described later, the obtained test piece was subjected to a chemical conversion treatment to form a chemical conversion film (zinc phosphate film) on the surface of the test piece metal fitting.

  Then, cationic electrodeposition coating was applied to each test piece obtained above. Specifically, as a cationic electrodeposition paint, a modified epoxy resin-based paint (manufactured by Nippon Paint Co., Ltd .: Powernics 110 Black) containing a modified epoxy resin as a main ingredient and a blocked isocyanate as a curing agent is used as an anode and A diameter of 20 cm × depth of 30 cm was placed in a stainless bat (container) to prepare a treatment bath. Then, while stirring the electrodeposition liquid in the treatment bath with a magnetic stirrer, the test piece was immersed in the electrodeposition liquid as a cathode, and the cation electrodeposition coating was performed at a treatment temperature of 35 ° C. and a treatment time of 3 minutes. Went. At this time, using the hole provided at one end of the metal fitting, the test piece is connected to the negative electrode side of the power supply device to be a cathode, while the container is connected to the positive electrode side of the power supply device to be an anode. . Further, as the applied voltage, since the area of the cathode (test piece) is smaller than the area of the anode (container), the applied voltage is lower than the applied voltage generally adopted in the actual mass production process: 160V (direct current) was adopted.

  Then, after taking out the test piece from the treatment bath and washing it thoroughly with water, it is further baked at 150 ° C. for 20 minutes to form a cationic coating film having a thickness of about 20 to 25 μm on the surface of the metal fitting of the test piece. Formed. And about this obtained test piece, while visually observing the surface of the rubber elastic body, the one where the paint is not attached at all is marked as ◯, while the one where the paint is slightly attached, The results obtained are shown in Table 2 below as x.

-Measurement of surface resistance value-
By vulcanizing and molding the anti-vibration rubber compositions according to Examples 1 to 6 and Comparative Examples 1 and 2 obtained above, a rectangular plate shape of length: 10 cm × width: 10 cm × thickness: 0.2 cm Each of the test pieces for measuring the surface resistance was prepared. Then, except that a 10 mm square electrode and an external dimension: 18 mm square × width: 2 mm electrode were provided on one surface of the obtained test piece using silver paste as shown in FIG. The surface resistance value was measured according to the method of “5.13 resistivity” of K 6911, and the obtained result is shown in Table 2 below.

As is apparent from Table 2, in Examples 1 to 6 having a surface resistance value of 1 × 10 ⁶ Ω or more, even if the cationic electrodeposition coating is performed without performing the masking treatment, the rubber elasticity It can be seen that there is no paint on the surface of the body. On the other hand, in Comparative Examples 1 and 2 having surface resistance values of 2.84 × 10 ³ Ω and 2.75 × 10 ³ Ω, respectively, the cationic electrodeposition paint adhered to the rubber surface.

It is a plane explanatory view showing an example of a vibration-proof rubber with metal fittings to which the present invention is applied. It is II-II sectional explanatory drawing in FIG. It is perspective explanatory drawing which shows the test piece for the electrodeposition coating produced in the Example, (a) is the metal fitting before vulcanization adhesion of rubber, (b) is the rubber after vulcanization adhesion, The integrated vulcanized products of the metal fittings are shown respectively. In an Example, it is explanatory drawing which shows the shape of the electrode formed in order to measure the surface resistance value of a rubber elastic body, Comprising: (a) is aa sectional drawing in (b), (b) The bb sectional view in (a) is shown, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Anti-vibration rubber with metal fittings 12 Metal fitting 13 Metal fitting surface 14 Convex part 16 Rubber elastic body 17 Rubber surface 18 Electrodeposition coating film

Claims (2)

Unvulcanized rubber made by blending 40 to 70 parts by weight of carbon black having a nitrogen adsorption specific surface area of 70 m ² / g or less with 100 parts by weight of unvulcanized rubber material is integrally vulcanized and bonded to a metal fitting. Then, a rubber elastic body having a surface resistance value of 1 × 10 ⁶ Ω or more is formed on the metal fitting to form an integrally vulcanized product, and then the electrodeposited vulcanized product is subjected to cationic electrodeposition coating. The electrodeposited coating film is formed only on the surface of the integrally vulcanized product without forming an electrodeposited coating on the surface of the rubber elastic body of the integrally vulcanized product. A method for producing a vibration rubber. Anti-vibration rubber with metal fittings formed by applying cationic electrodeposition coating to an integrally vulcanized product of rubber elastic body and metal fittings,
The rubber elastic body is vulcanized using unvulcanized rubber obtained by blending 100 parts by weight of an unvulcanized rubber material with 40 to 70 parts by weight of carbon black having a nitrogen adsorption specific surface area of 70 m ² / g or less. is formed by vulcanization bonding, with has a 1 × 10 ⁶ Ω or more surface resistance, without the surface of the rubber elastic body electrocoating film is formed, only on the surface of the metal member, An anti-vibration rubber with metal fittings, wherein an electrodeposition coating film is formed by the cationic electrodeposition coating.

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