What types of applicator technologies are commonly used in direct coating processes for applying the release coating to silicone release paper?

There are several types of applicator technologies commonly used in direct coating processes for applying release coatings to silicone release paper. These technologies are designed to ensure accuracy, precision, and even distribution of the release coating to achieve optimum release properties. Here are some commonly used applicator technologies in direct coating processes:

1. Knife Over Roll (KOR): This is one of the most widely used coating methods for applying release coatings. In this process, a knife blade is positioned above a roller that carries the silicone release paper. The coating material is fed onto the roller and is metered by the blade's adjustable gap. As the release paper passes under the knife blade, a controlled amount of coating is transferred onto the paper. KOR ensures uniformity and precision in coating thickness.

2. Meyer Bar: The Meyer Bar coating technology is another popular applicator method for applying release coatings. It involves using a stainless steel rod or bar with a precise and predetermined gap between the rod and the substrate (silicone release paper). The release coating is poured on the substrate, and the Meyer Bar is used to spread and control the coating thickness across the surface. The height of the bar determines the coating thickness, while the speed of the substrate controls the amount of coating applied.

3. Gravure: Gravure coating uses a cylindrical roller engraved with tiny cells or pits that carry the release coating. The roller is partially immersed in the coating material, allowing the cells to be filled. Doctor blades are used to remove excess coating from the roller surface. As the silicone release paper passes over the roller, the release coating is transferred onto the paper through the engraved cells. Gravure coating allows for high precision and consistent coating deposition.

4. Slot Die: Slot die is a non-contact coating method that uses a precision-metered die to apply the release coating. The die has a narrow, rectangular-shaped slot from which the coating material flows onto the silicone release paper. This slot die system provides a uniform and controlled coating thickness across the width of the substrate. is often used for wide web applications.

5. Air knife: In the knife coating method, the release coating is applied to the silicone release paper using pressurized air stream. The air stream helps distribute the coating evenly across paper's surface, while the airflow controls the thickness of the coating. The excess coating is removed by blowing air at an angle, leaving behind a precisely coated layer. Air knife coating allows for high-speed and continuous coating processes.