Requirements on the composing of sealing materials

Over the years, the EU Plastics Directive has developed to become the most comprehensive set of rules for packaging in contact with food. Numerous amending directives, positive lists for additives and monomers, specified limit values for individual substances and details on the scope of declarations of conformity through to the so-called "Super Regulation" and the Plastics Implementation Measure (PIM), have extensively documented the requirements to be complied with. For sealing materials, these include the fact that under normal, predictable conditions of use, no components of the sealing material may migrate into food in volumes which could represent a risk to human health. Nor may there be any unacceptable change in food composition and the organoleptic properties of food – smell, taste, appearance – must not be impaired.

Accordingly, each individual component of the sealing material must be examined critically in terms of a possible hazard potential. These raw materials must be firmly integrated in the sealing matrix so that they cannot be rinsed out. Nor may auxiliary agents used during processing (e.g. organic solvents, interlinking chemicals) leave any residue in the sealing material.

These requirements speak for TPE materials available in granulate form which are shaped as required by means of thermal forming processes. Interlinked or other reactive additives are not necessary with the result that nothing can migrate.

One reason for developing PROVALIN®, the first and to date only sealing compound free of PVC and plasticizers for metal vacuum closures. “While developing PROVALIN®, we examined all of the possibilities from every conceivable aspect. From liquid solutions through PU and water-based formulations. Considering our desire to comply with or even outperform legislative specifications which have become even more stringent with the current EU 2011/10/EG Directive, PROVALIN® is by current standards not only the best but the only solution available”, emphasized Wilfried Lassek, Managing Director of Actega DS, the company which developed this compound. “Including in terms of its range of applications, production efficiency and cost structures our compounds are the right solutions”, underlined the company.

A wide range of applications is meanwhile available enabling practically all requirements involving contents, closing processes, storage and closure sizes to be complied with. All types of contents can be safely packaged beyond the overall BBD. There are no restrictions during the filling and sealing process, including hot or cold filling or even thermal post-treatment such as pasteurization and sterilization. After a lengthy and complex development phase and an initially gradual introduction phase, this PVC-free closure has meanwhile become a success story:

Exhibitor Data Sheet