The arrangement for tethered caps to plastic bottles is intended to help stem the flood of waste. At the same time it promotes the sales opportunities for Uddeholm's plastic mould steels for the production of new caps.
Environmentalists collected more than 1.5 million plastic bottle caps from the world’s oceans beaches in a single day at this year’s “International Coastal Cleanup”; small parts that would otherwise be torn out to sea by waves and tides and end up in the food chain. This is one of the reasons why the EU Directive 2019/904 on environmental protection stipulates that from July 2024, plastic bottle caps of up to 3 litres must remain attached to containers. Lined, so to speak. “The packaging industry must respond to this regulation with solutions that do not allow the separation of closure and container,” explains Riccardo Zanchetta.
The manufacturer’s challenge
As Head of Technical Department Uddeholm in Milan, he is familiar with the requirements that the new regulation places on producers:
"To make it more difficult to tear the cap off the bottle, the material thickness must increase–even if this runs counter to the trend towards minimising the use of plastic materials."
Zanchetta is in close contact with the country’s most important manufacturers, who need new injection moulds to meet this challenge: “One customer confirmed to me that, especially with the high complexity of the ‘tethered caps’, tool steel with many special properties, e.g. hardness, wear and corrosion resistance, is needed.” The customer stressed that steels such as Uddeholm’s Tyrax ESR would give the injection moulds the required performance and reliability.
Solving two problems with one cap
“These particularly high performance mould steels from Uddeholm will be used for the new moulds for redesigned caps,” explains Henrik Nöbauer, Product Manager Plastic Mould Steel at Uddeholm. Because they allow the use of sustainable bio-plastic materials because they can withstand their more aggressive behaviour. So when beverage closures are “tethered” in four years’ time, the use of Uddeholms will also stand for more sustainability.