SEPAWA® CONGRESS 2022 

Speaker: Arnold Uhl

Company: LUM GmbH

Title: Multisample Coating Strength Testing for Cosmetic Packaging

Abstract: The application presented deals with the determination of the adhesive strength of metal-coated polymers using the example of lids for perfume bottles and cream jars. On the one hand, gold or silver-colored coatings must be opaque and abrasion-resistant, and on the other hand they must be as thin as possible for economic reasons. The measuring principle of CAT technology (Centrifugal Adhesion Testing) is used. It can be described as an automatic determination of the strength of up to eight specimens to be tested simultaneously. Due to the rotation of a rotor, the centrifugal force acts on the test specimens located in the rotor. This is used as a test force. Increasing the rotor speed increases this force. As soon as the maximum load capacity of a test specimen is reached, the test stamp separates from the substrate. The detachment event is recorded online and transmitted in real time via a position-based signal to a stationary receiver, which sends the information to the SEPView 7 measurement and evaluation software. The breaking force is automatically calculated based on the mass of the test stamp m, the distance to the axis of rotation r and the critical speed n and is currently displayed on the measuring PC. In addition to the tensile stress, in which the force acts perpendicular to the plane of the adhesive layer, shear strength can also be determined by using specially designed test specimens. The tested sample systems included lids for packaging of cosmetic products from two different production stages (""Red"" -intermediate product stage; ""Blue"" - complete layer system). The primary aim of the experiment was to find out whether layer delamination occurs and to what extent additional layers of the multilayer system affect the surface properties. The determined strengths and exemplary fracture patterns are discussed.