Connected closures are key in combatting plastic litter

Initially greeted with dismay by the world’s major beverage companies, the tethered cap legislation proposed in 2018 and adopted in 2019 by the EU as part of the Single-Use Plastics Directive (SUPD) will come into force this year, making attached caps of one kind or another a fact of life for consumers throughout the EU from July 2024.  

When the plan to make tethered caps a mandatory requirement was first floated, various multinationals, including Coca-Cola, Danone, Nestlé and PepsiCo, vigorously opposed the idea. Such a requirement, they pointed out, might seem minor, but it would involve vast amounts of time, effort and investment. New designs, new moulds, often, too, new machines would be needed, none of which would be achievable within the envisioned time frame.  
According to these household-name companies, it would be far preferable to focus on improving existing recycling systems rather than investing in new tethered cap designs.  Their position was bolstered by a study conducted by PricewaterhouseCoopers for the European soft drinks industry (UNESDA) and European Federation of Bottled Waters (EFBW), that outlined the significant environmental and economic cost of implementing the European Commission’s proposed mandatory tethered caps on beverage containers (article 6 of SUP directive). 
To no avail, however. The EU’s Single-Use Plastics Directive, aimed at, among others, reducing unintended environmental waste and facilitating the recycling of caps and closures along with their containers, was adopted with record speed, including the stipulation that plastic caps must remain attached after opening on all single use plastic beverage containers of up to three litres from July 2024 onwards. Metal and glass containers are exempt from this obligation. The measure is expected to prevent 10% of plastic litter found on European beaches.  
The legislation, intended to be transposed into national law by 3 July of 2021, has not been a completely smooth one, with various member states lagging behind in different application areas. However, the tethered caps and lids requirement is one that has unleashed a wave of innovative closure designs.  
As the Directive states, “plastic closures and lids used for beverage containers are among the single-use plastic items most frequently found as litter on the beaches of the European Union. Therefore, the placing on the market of single-use plastic beverage containers should only be allowed if they comply with certain product design requirements to significantly reduce inputs of plastic container closures and lids into the environment.”  

To that end, a standardisation request was issued by the European Commission to the standardisation body CEN to develop a standard on how to manage this change in design – which request was subsequently adopted by the member states. The standard had to be robust enough to ensure caps and lids were of appropriate strength, reliability and safety while remaining attached to the beverage container during the product’s use, in order to adequately fulfil the goal of the tethering requirement. Considerations included tooling design, the weight of the cap and the cap manufacturing process, with brands, packaging producers and equipment suppliers joining together to create compliant solutions. 

In March of 2021, Austria-based plastics machinery manufacturer Engel published a blog in which, among others, the author specifically set out the requirements for the design and function of tethered caps resulting from the new regulation. According to Engel, the new closures had to: 

·       Be compatible with existing preform designs, openings and thread types; 

·       Have the lowest possible impact on customer interaction, i.e. comfort of use should not be reduced; 

·       Be compatible with existing filling equipment; 

·       Remain connected to the container throughout the entire product life cycle until recycling; 

·       Be produced from the same materials;  

·       Minimally impact existing production lines and result in no reduction of output;  

·       Be able to be opened and closed over 15 times without compromising the integrity of the cap; 

·       Feature a connection between cap and container able to withstand at least a 25 N tensile force. 

Although its development was marked by delays, on 30 May 2023, the new harmonised standard for test methods and requirements to demonstrate that plastic caps and lids remain attached to beverage containers was published in the Official Journal of the EU. 

Design solutions 
A variety of solutions have been developed to produce attached caps that comply with the standard. Broadly speaking, manufacturers of caps and closure systems have pursued two main approaches, namely the development of hinged tops and of lasso closures. Both approaches offer a slew of different concepts, with considerations depending on the type of machinery already in use and the associated costs of modifications required. 
These associated costs are a key consideration for the whole supply chain involved in the single use beverage market, as customer surveys and sales meetings alike show that adding a cost to the consumer is unlikely to be well received. So, the tethered closure that offers legal compliance alongside little or no additional cost is king. 
Supplier of machines and complete plants for the packaging industry Sacmi has led the compression technology market for over 20 years, offering a combination of support and technical capabilities for all types of closures. Head of group PR and communications Valentina Gollini shares that its wide range of both standard and tethered closures are available, with a particular demand increase seen for tethered closures for 26/22mm necks. Gollini says, “Sacmi has developed the widest range of caps on the market, certified by leading international brand owners that comprehensively supports customers’ product development journey, offering the best solution in terms of both functionality and design. Our proposal for manufacturing plastic caps involves slitting the tamper evidence band, both traditional and tethered, through a machine located downstream of the press. The slitter receives the already-oriented caps and handles them using rotary spindles; the caps interact with one or more knives that partially cut the wall of the caps. The molded caps have a straightforward design because they lack the complicated structure of the band.” 

One packaging producer that has chosen the Sacmi machinery as part of its portfolio of tethered closure production is Retal, who has needed to adhere to its global beverage brand customers’ wholesale adoption of the SUPD regulations. By utilising its in-house design team, with access to sophisticated CAD technology and its relationship with machinery partner Sacmi, Retal has developed a tethered closure using compression technology that has no cost to its customers as it is just a simple adjustment in the slitting tooling. Anton Sugoniaev, head of R&D, explains, “We call this our EasyTether. We can show our customers how it allows them to be in good time for the legislation, with no cost to them or changes to their production line. It’s important to be able to look differently at a problem, to be open-minded about a potential solution; don’t forget that these caps with a remaining connection would have previously been considered defective!” The EasyTether adds to Retal’s 1881 tethered portfolio with conventional hinge system, and is joined by its 1810, 29/25 and 26/22 compatible tethered closures. 

Brand benefits 
Packamama, the team behind the traditional wine industry-disrupting flat rPET wine bottles, have been similarly quick to adopt this sustainability-driven tethered closure, particularly as its name is synonymous with progressive packaging. Alex Adda, leading the tethered closure project for the company that rebranded from Garcon Wines in 2022, says, “"EU Directive 2019/904, stipulating that from July 2024 onwards plastic caps on all beverage bottles of 3 litres or less must remain attached to the bottle after opening, was announced in 2019. This five-year period was more than enough time for all companies to prepare for this, even if a new cap needed to be created from scratch. Keeping the cap attached to the bottle is a sensible approach to capturing this material for recycling. The technologies exist to allow for tethers to be offered and if completed properly, this has no impact on the experience for the consumer. However, it does allow for valuable material not to be lost in the process. For this reason, at Packamama, we support the legislation. We commenced engagement with our cap supply partner on this in February 2021 and we already have a solution that can be utilised as the legislation should come into force this summer. Packamama offers the future of wine packaging today. We supply our novel eco-flat wine bottles to leading wine producers and retailers to engage consumers and to save cash and carbon from wine's supply chain. Our multi award-winning bottles are flat-pack designs to save space and are made from 100% recycled PET to save weight and energy; slashing emissions and offering a competitive advantage." 

The implementation of tethered closures for single use plastic beverage packaging up to three litres may currently only be an EU legislation but it is likely that this is just the start. As Sacmi’s Valentina Gollini says, “Even if the tethered standard will become mandatory in the European community within July 2024, we see an expansion beyond the European borders where it is expected to be voluntarily adopted in different markets and areas. Standardization, sustainability, and differentiation are some of the drivers of this transition. Economic sustainability too. Regardless of mere payback time, a cap manufacturing line is a durable commodity with an average life typically close to ten years. During this time, the market and its regulations can undergo radical changes, as is happening with the introduction of the tethered cap.” 

With responsible nations leading the way, it is expected that more countries will see regulations forcing the adoption of attached closures for convenient beverage packaging, including the US, with California passing the AB793 mandate for recycled content in 2020, and Australia, where a wide-reaching strategy for reducing ‘problematic’ plastic use includes a proposal for banning takeaway containers by 2025. As long as the key players in the plastic packaging supply chain stay forward-thinking, this is cause for celebration rather than concern. With global brands welcoming the practicalities of standardised procurement and plastic packaging producers keen to be part of the solution, the tighter regulations offer an interesting – and welcome – challenge.