Water based MICA primers are formulated to adhere to polymeric films,paper and foil. Unfortunately,many of the primers are also prone to bonding with chrome and ceramic applicator cylinders, metal machine parts and , frankly, most equipment on which they are allowed to dry.

Don't over-apply. Don't under-appy. How do we select the best cylinder for delivering the appropriate amount of primer?

Many flexible plastics converters extrude low-density polyethylene ("LDPE") on a daily basis. This resin is easy to process and meets the customers' requirements for adhesion, cohesion, and chemical resistance. IN some cases however, polyethylene is not the resin of choice. For example, if elevated temperature resistance or grease resistance are important, polypropylene might be a better choice. Although there are many ...

Mica extrusion coating primers have been developed for single-pass processes. The best performance will always be achieved when the primer is applied immediately prior to extrusion coating.

Sometimes, however, there is a need to perform a multiple-pass process, where a substrate is primed, dried, rewound and stored for later use.

Do we have to prime if we treat? Do we have to treat if we prime? The answer is YES to both questions, when extrusion coating onto film substrates such as polypropylene.

The function of a chemical primer is to enhance adhesion and contribute product resistance to a converted structure.

In our last issue of Primer Intelligence, we described the heroic effects of flame and corona discharge treatment. Now it is time to back-peddle a little and warn of the risks inherent in too much of a good thing.

Primer application is not limited to gravure systems. Many converters have found smooth roll applicators well suited to apply MICA water based primers.

Adequate oxidation of an extrusion coating resin in the air gap is critical for adhesion to the primer.