Even if there had long been a demand for PVC-free solutions for metal vacuum seals and plenty of experience had been acquired in-house with PVC-free material developments, the challenge was to find such a solution for Twist-Off® seals. Unlike PVC-free crown corks or aluminum seals, new plants would have had to be designed especially for these PVC-free seals. The classic PVC plastisol machines were not suitable for the newly-developed PVC-free materials. Here at the latest, it was clear that the development would involve high investments on the part of closure manufacturers and many people advised against it at the time. This was one of the obstacles which not only concerned product development but also the environment if it was to be a commercial success at all. All the same, certainty prevailed that it was the solution of the future. Particularly for the area of canned food where metal vacuum seals are used, the use of sealing materials free of PVC and plasticizers was of major significance on account of the problems associated with migration by plasticizers into food. This was also reflected in the increasingly tight EU and Foodstuffs Ordinance. Accordingly, it was obvious that by simply tightening the migration limits, only systems free of plasticizers would be successful over the long term. It was imperative, therefore, to protect PROVALIN® technology by registering it for patent and an application was submitted in 2007.
With an interested customer (Pano) and a purchaser (Dittmann), there was a perfect combination available as required for launching new products: expertise and the requisite plants for manufacturing the seals on the one hand and a manufacturer of branded goods on the other. These initiative partners provided the requisite technology boost and market pull for making such a lengthy and complex development a lasting and sustainable success. And a contribution was also made by the collaboration with Actega, Grevenbroich. After all, a Twist-Off ® seal not only comprises the metal cover and the sealant material but also adhesive inside varnishes and exterior lacquers. Many different raw materials had to be tested first in order to establish how the materials relate to each other. And the premise was also to develop BPA-free materials – another challenge, particularly with regard to resistance to acidic filling goods. These BPA-free adhesive varnishes are now available today.
The material formulations developed need to be tested and examined extensively, including in terms of their processability and function. Initially, there was only one laboratory machine available which glued the compound (today: ring-liner technology) into empty shells which were then sent to Pano for rolling on before coming back to us. Development of a hand tool made it possible to shorten these lengthy development routes somewhat but it was still anything but optimal. Today, the Actega team can look forward to a new Sacmi plant which is to be available within 2021, making it possible to react even faster, more effectively, and more targetedly to market requirements. What's more, entire steam-vacuum sealing machines and pasteurization chambers are also available, enabling us to depict the entire closure manufacture about bottling, closing, heat treatment. Which means it will be possible to adapt the PVC-free seals to the respective legislation or market situation in the years and decades to come even faster. Major investments and the extensive expertise developed as a result, enabling the realization of innovative products and top customer service, are the keys for long-term success.
The first area of application entailed oily products in the area of delicatessen products, e.g. pepperonis in oil. Practically a niche launch. This was soon joined by cold-filled products such as cheese cubes in oil which represented yet another challenge as it entailed filling under cold conditions. A new compound had to be developed for this application – one which would stay tight yet be easy to open after storage in the refrigerator. The topic of sterilization was also broached at an early stage, e.g. as required for olives, classic sausages etc. This in turn shifted the focus to jar stacking. Answers were required concerning the sealing results on fast-moving plants as well as particularly soft materials requiring less steam yet sealing equally well. Other requirements arising from the market are implemented optimally following intensive examination. Accordingly, the existing portfolio has been steadily improved and will continue to be further optimized.
What started as a niche product is now a firm component within the market. But this market is constantly in motion. New challenges can arise at any time, e.g. on the part of the filling industry, where the topic of sterilization has already been under discussion for some time now in terms of increasing the temperature to reduce the time for sterilization. Or on the part of the legislative bodies if, for example, materials such as additives in food contact are evaluated differently by the FDA or the EU or there is a shift in migration limits. Or the glass currently undergoing a renaissance will be replaced by containers made of PET or polycarbonate in the future. These are all key stimuli for innovations and new developments offering the filling company benefits such as improved handling, more extensive areas of application, the elimination of unknowns concerning regulations, and much more.
The development has attracted a certain degree of attention in the market which has also led to PROVALIN® receiving several awards. In 2011, PVC-free sealing systems in Actega’s Altana division won the annual Altana Innovation Award. This prize was awarded for PROVALIN® and the corresponding varnish systems. Also in 2011, in the “Design and Processing” category, the “PVC-free cam screw cap Pano Blue Seal powered by PROVALIN®” received the German Packaging Award. The heart piece of this seal is formed by the PVC-free PROVALIN® sealing compound. This was the first time a PVC-free seal was established in this market segment. Following a development phase extending over many years on the complex Press-On Twist Off® seal project and an extremely time-intensive test and trial time, the SOPURE 51 seal by Pelliconi with the PVC-free PROVALIN® sealing compound has been in commercial use since early 2018. It received the Canmaker Gold Award for the PVC-free Press-on Twist-off® seal for baby food within the framework of the Can of the Year Award. Since 2020, this compound has been offered under the name of ACTGreen® PROVALIN® for better identification as a green sealing ring. Now with more than two billion twist-off seals per year on the European market, the PVC-free seal has meanwhile achieved a general market penetration.