Bonding systems primer/cover-coat

The level of environmental resistance required and equipment available may determine whether to evaluate primer/cover coat systems versus one coat adhesive systems. And last, but not least, cost of both the adhesive and the application process is an important factor to consider in any industrial application, rubber to metal bonding being no exception. 

Bonding agents are applied as one or two coat systems. The primer coating is formulated to have good adhesion to metal and consists of polar materials dissolved in suitable solvents. The cover coat may consist of a mixture of several polymers, usually of intermediate polarity and rubber like, rather than resinous in nature. The formulation involves considerable knowledge and is very complex in nature. 

All test samples were bonded with a two-coat adhesive system consisting of a metal primer and a cover adhesive. A metal primer is necessary because the cover adhesive exhibited very little inherent metal adhesion. Metal primers used in this study included one commercial and three experimental primers. One commercial and six experimental cover adhesives were included in the testing. 

This guide covers one-coat shop painting systems for steel that will not be exposed to corrosive conditions for long periods. They are also suitable for steel encased in concrete in those oases where bonding of steel to concrete is not required. They can be used under fireproofing. These systems are suitable for use on parts or structures exposed in Environmental Zones 0 (encased in concrete or masonry, normally dry) and lA (interior, normally dry). The paints covered by this guide are primers, and if a color other than the standard color is required, the color must be specified. 

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