Case Studies: Functional Packaging

Mitsubishi Chemical Advanced Materials Creative Molding & Systems (Mitsubishi Chemical Advanced Materials CMS) is supporting Dispack Projects in creating a new generation one-way PET beer keg with a recyclable, innovative valve system as a cost-effective and easy-to-transport alternative to traditional multi-trip stainless steel kegs.

Dispack Projects’ new one-way DOLIUM® 20- and 30-liter kegs incorporate valve systems injection molded in glass reinforced polyamide, as well as protective, stability-adding external keg rings for improved handling and storage. Both elements were designed and developed through close co-operation between Mitsubishi Chemical Advanced Materials CMS, a fully-integrated manufacturer of injection molded polymer components and sub-assemblies headquartered in Tielt, Belgium and Dispack Projects.


To develop a cost-effective and more environmental friendly option for the beer industry, Dispack’s founder Albert Wauters, draught and keg expert, had to ensure that product integrity, food safety regulations and an extensive list of performance requirements set by beverage producers, distributors and end-users would be met by the keg and its various accessories, including an integrated pressure relief valve system.
At the same time, priority was also given to limiting the operational impact versus the traditional keg by achieving compatibility with existing filling lines and draught equipment.
In line with these factors, the partners chose the market’s four most popular metal valves and their corresponding couplers as the main reference points for the development.

“Converting applications from metal to plastics is something we’re very familiar with at Mitsubishi Chemical Advanced Materials however close collaboration with the customer is needed to lead the development process to a successful application,” comments Jan Claeys, Account Manager at Mitsubishi Chemical Advanced Materials. “For this project we had to follow both a conservative and innovative approach as not much space was given for major design adaptations. We had to take into consideration the need to match the new plastic valves with the existing couplers in the market, and Dispack’s desire to preserve the handling & safety requirements especially by integration of a pioneering internal pressure relief safety feature.”

For the final DOLIUM® PET kegs, Dispack and Mitsubishi Chemical Advanced Materials CMS developed new valves in four different versions that can be used with the most common couplers on the market for connecting kegs to draft dispensing systems. Particular attention was given to accommodating DOLIUM®’s plastic valves to the variations in tolerance of the metal couplers from different manufacturers. The system uses glass reinforced polyamide.

The development of the new one-way DOLIUM® beer kegs involved extensive use of computer-aided design and engineering, as well as production of rapid prototypes. Final testing of the accompanying top and bottom handling rings as well as the valve system and the safety pressure relief valve have been carried out on parts made on single-cavity prototype molds before final multi-cavity molds were built.

The new DOLIUM® one-way beer kegs offer extra benefits to existing one-way PET versions available on the market. Offering the four variants of the plastic valve systems for example, customers have no need to investment in modifications for the filling of the kegs or for connecting them to the draft systems.

The keg, with its special top and bottom rings made by Mitsubishi Chemical Advanced Materials CMS, has been designed so that it can be handled in vertical and horizontal way without the need for a supplementary protective cover. The rings make the keg stackable and ensure that it is protected during handling.

Albert Wauters, founder of Dispack and inventor of DOLIUM® one-way beer keg design, adds: “DOLIUM® One-way PET kegs offer several important advantages over the multi-trip stainless steel version. Confirming the DOLIUM® shelf-life equal to stainless steel kegs, brewers can avoid huge capital investments in pools of metal kegs that have a very low yearly rotation, especially in use on long distance. By optimizing the outbound shipment – efficient geometry replacing the stainless steel weight by more product - and by avoiding long distance return transport, we skip important transport costs as well as the excessive energy consumption of empty stainless steel kegs, Together with the 100% recyclability of the DOLIUM® one-way kegs, this results in better environmental performance. The transport of heavy metal kegs clearly poses a higher environmental burden than a fully recyclable plastic keg. With its innovative features, we expect sales and interest in DOLIUM® to continue to rise and we are preparing to ensure we can meet increased demand with the addition of more molds.”