In order to properly bond rubber to metal, the rubber is glued to the metal through the use of multiple adhesives. Then the mold gives the rubber its shape when it is being bonded to the metal. In the past, steel was, by far, the most commonly used metal in this process. Today, aluminum takes that’s position. Aluminum is much less costly and it weighs significantly less than steel. Furthermore, it maintains these features without compromising the quality or strength of the product. The rubber material can also be natural or synthetic, containing silicon, neoprene and nitrile.
There are products within many industries that utilize metal bonding, including the automotive, aerospace, construction, and rubber roller manufacturing industries. Silicon bonding, however, is used most commonly in the production of surgical instrument handles and other products such as rubber-lined rollers, engine mounts, electrical cables, reinforced tires and more.
When manufacturing rubber-to-metal bonded products, there are three main components in the process: the rubber material, the bonding agents and the metal substrate. Almost any type of rubber can be used as long as it can flow without developing cross-linking and it does not bleed to the surface of the uncured stock. The bonding agents contain solutions based on solvent or water, while the primer coat is based on phenolic-style resins and a topcoat of polymers and other materials. Also, if the part is not going to be exposed to high temperatures, humidity or pressure, a single coating of bonding adhesive will suffice.
The nature of the rubber formulation dictates the thickness of the bonding layer. Bonding agent application requires a coat of gray primer over a slightly larger area than than black topcoat. This is done using a low-pressure, high-volume-barrel spraying machine. As for the type of adhesive material, it is dependent on a two factors: the operating conditions of the finished part and the rubber and metal used as the materials.