JPH0455589B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a method for producing vibration-proof rubber having excellent corrosion resistance.

<Prior Art> Anti-vibration rubber is used to provide anti-vibration support for machines that generate vibrations, or to provide anti-vibration support so that external vibrations do not affect precision instruments. Furthermore, many anti-vibration rubbers are used in automobiles, such as for engine support and suspension components.

These anti-vibration rubbers are often adhesive composites of metal and rubber, and in order to prevent corrosion of metal parts such as iron, they have traditionally been painted with melamine/alkyd-based water-based paints or lacquer-based paints. There is.

<Problems to be Solved by the Invention> However, vibration isolating rubber for machinery used in the Kaiito area and vibration isolating rubber for automobiles that are affected by chlorides sprayed to prevent road surfaces from freezing in cold regions, Due to these salt damages, conventional coatings have insufficient corrosion resistance for metals, and countermeasures are urgently needed.

On the other hand, it has been known that high-temperature baking-type coatings such as powder coating and electrodeposition coating are suitable for corrosion protection of metals without rubber composites; Due to the high temperature of 160°C or higher, when rubber is used as a vibration-proof rubber composite with adhesive, there is a problem in that the rubber and adhesive parts deteriorate when the coating cures. Another reason why electro-deposition coating has not been used for anti-vibration rubber is that generally many anti-vibration rubbers have two or more metal parts with rubber having high electrical resistance interposed between them. The problem is that even if electricity is applied to one part, it does not conduct to other metal parts, and that part cannot be painted.

Therefore, the present inventors developed a structure in which the metal members were separately electrodeposited and then integrated with vibration-proof rubber by adhesion, and this was previously proposed in Japanese Patent Publication No. 51905/1983. However, this product had the disadvantage that the coating film on the adhesive part had poor heat resistance, which limited its use.

<Means for Solving the Problems> The present invention solves the above-mentioned difficulties by applying electrodeposition coating, which has excellent corrosion resistance, to a coating film at a relatively low temperature that does not affect thermal deterioration of rubber and adhesive parts. hardening, in the case of items consisting of multiple metal parts,
This problem was solved by performing electrically conductive treatment in advance and applying electrodeposition coating.

In other words, electrodeposition coatings used as undercoat coatings for automobiles are usually cured at high temperatures of 160°C or higher, and have a paint film hardness of 3H to 4H on a pencil hardness required for undercoat coatings, but in the case of anti-vibration rubber, Since it is a top coat, it is rather too hard and tends to cause chipping. Therefore, the present inventors cured the electrodeposited coating at a low temperature of 150°C or lower, which does not affect the rubber or the bonded area, thereby achieving coating hardness comparable to HB and excellent pitting resistance. They discovered that corrosion resistance can be maintained.

Furthermore, to solve the problem of not being able to paint other metal parts when electricity is applied from one metal part, conductive treatment is a method of blending conductive carbon black and graphite into rubber, and a method of applying a conductive primer composition to the rubber surface. For example, by applying a solution of a quaternary ammonium salt, or by using a jig such as a spring steel connector having two or more contacts on at least one side, as shown in the examples below, metal The purpose is to enable electrical conduction between the parts.

<Function> According to the present invention, since the electrodeposition coating is cured at a low temperature of 150°C or lower, the chipping resistance of the coating film is improved, and the effect of preventing thermal deterioration of the rubber and adhesive parts is achieved. be. Furthermore, even if the product is made up of a plurality of metal parts, if electricity is applied from one of them, all metal parts can be painted in the same manner as in the conventional dipping method.

The present invention will be explained in detail below with reference to Examples.

<Example> Before electrodeposition coating, spring steel was applied between the metal parts 3a and 3b provided on both sides of the rubber elastic body 2 of the anti-vibration rubber 1 as shown in FIG. 1 which had been cleaned with pure water. Conductive treatment was performed using a connecting jig 4. The spring steel connection jig 4 used here has at least one contact point 5 connected to 2
A structure with two or more pointed four-point support contacts on both sides of an expandable spring material as shown in Figure 2, or a structure with two pointed four-point support contacts as shown in Figure 3. , having three-point support contacts, two on one side and one on the other. Alternatively, a simple material such as a wire rod may be used. Since the metal members 3a and 3b are electrically conductive due to these contacts at both ends of the connecting fitting, when a commonly used energizing jig 6 is connected to one metal member 3a, the entire metal member is energized. This makes it possible to perform electrodeposition coating. In this state, an epoxy-based cationic electrodeposition paint (product name: Power Coat, manufactured by Nippon Paint Co., Ltd.) was applied by electrodeposition, and then cured at 140°C for 40 minutes.

As a result, the hardness of the coating film formed on the metal part of this anti-vibration rubber is HB on the pencil hardness scale, and is JIS
Z2371 passed the salt spray test for 240 hours, and the rate of change in static spring characteristics before and after painting was less than 5%, which is within the range of no practical problems.

<Effects of the Invention> As detailed above, since the present invention cures the coating film at a low temperature of 150°C or lower, conventional anti-vibration rubber coated with a melamine alkyd resin can be cured for up to 96 hours in the salt spray test. According to the present invention, the corrosion resistance was improved to 240 hours or more without impairing the vibration damping properties as a vibration isolating rubber.

Furthermore, due to the conductive treatment applied before electrodeposition coating, even if the metal parts are separated, they can be coated in one layer just like conventional dip coating.
Electrodeposition coating can be applied simply by hanging two metal parts on a current-carrying jig (hanger).

[Brief explanation of the drawing]

FIG. 1 is a front view showing the state during electrodeposition coating, and FIGS. 2 and 3 are exemplary perspective views of the connecting jig. 1... Vibration-proof rubber, 2... Rubber elastic body, 3a, 3
b... Metal member, 4... Connection jig, 5... Contact,
6...Electricity jig (hanger).

Claims (1)

[Claims] 1. A method for producing a corrosion-resistant vibration-proof rubber, which comprises bonding metal and rubber, applying electrodeposition coating, and curing the coating film at a low temperature of 150°C or lower. 2. Claim No. 2, characterized in that, in a vibration-proof rubber consisting of a plurality of metal parts with rubber interposed therebetween, a conductive treatment is performed between the metal parts prior to electro-deposition coating, and electricity is supplied from one metal part. A method for producing a corrosion-resistant vibration-proof rubber according to item 1.