Optical measurement of the thickness of an individual layer in a plastic multilayer compound

摘要

In plastic multilayer compounds the functionality of the system is often provided by a single functional layer. This is the case for food packaging materials, floor heating or gas pipes for example. The functional layer alone is responsible for the functional features of the system, e.g. diffusion impermeability, and is deposited on a cheap plastic substrate like PP, PVC or PE using an adhesive. In such systems, the thickness of the substrate typically exceeds the thickness of the other components considerably. The materials used for these functional layers often are comparatively expensive, which makes it desirable to have these layers as thin as possible.