Modification of EPDM seals to prevent aroma carry-over during the bottling of wine

The absorption of aroma compounds in seals during the bottling of wine and the migration of these aroma compounds into the subsequent bottling process is a major problem in the German wine industry. In order to meet the legal requirements, for example, the seals used up to now have to be replaced with more expensive alternatives. However, these alternatives are not suitable for every area of application. An alternative to this is the use of modified ethylene-propylene-diene-rubber seals, which have a lower aroma compound carry-over. In a research project, new and inexpensive ethylene-propylene-diene-rubber seals were developed which minimise migration into the subsequent filling process. The seal material and the surface of the seals were modified. Within the scope of the research, compounds of different fillers were prepared and examined for their migration properties of critical aroma compounds. Furthermore, the influence of the degree of crosslinking, the ethylene content of the basic rubbers used, the plasticisers used and the influence of the surface roughness of the seals were also examined. The seals were coated using low-pressure plasma in order to describe the migration of selected aroma compounds depending on the surface properties. In addition to the migration properties, the influence of the fillers used on mechanical properties such as elongation at break and compression set was also measured, since seals have to fulfil a wide range of requirements. By means of statistical test planning, the observation was carried out in effect and contour diagrams in order to create an optimised sealing material on the basis of the resources used.