Simulation with Silicone - Wacker Chemie AG


Simulation with Silicone

The pilot coater at the new DEHESIVE® Coating Center in Burghausen: WACKER engineers work on a 380-square-meter area to simulate industrial processing conditions for silicone release coating.

At the pilot coater, a 1 to 1.3-µm-thin layer is applied to the backing material and then dried in an air-flotation dryer at 100° to 180 °C – depending on the material properties – for 1.2 to 18 seconds. Here, the WACKER experts simulate the customer’s industrial processing conditions exactly.

The subsequent use of the release liner is also of great importance. In industrial labeling, a machine applies up to five labels per second to packaging – such as a shampoo bottle. The skill of the laminate manufacturer now lies in finding a compromise in the release force between the label and the release liner so that both matrix peeling and labeling run smoothly.

Double-sided adhesive tape poses another challenge for laminate manufacturers. The release liner must feature two different release forces for the two sides, so that the adhesive tape peels off of the underside of the release liner first. This allows the double-sided adhesive tape to cleanly peel off for further processing.

At the DEHESIVE® Coating Center lab, WACKER engineers determine the release-force profiles of different coatings using customary test methods.

Testing with X-Rays

On a lab bench of the DEHESIVE® Coating Center, a color test provides information on the level of cover of a coating right after it has been applied. X-rays measure the thickness of the applied silicone release layer. After it has cured, the release coating still contains reactive groups that can interact with the adhesive during storage. That’s why WACKER engineers also perform long-term tests to ensure that the release coating still meets quality requirements after prolonged storage. To determine whether the curing reaction is complete, the coated substrate is placed in solvent, which dissolves out any uncured silicone. The amount of such uncured silicone is then measured analytically. As a result, the amount of platinum required can be determined precisely. Optimizing the formulation can therefore reduce platinum consumption by as much as one-third.