Whatever the tether

While all plastic packaging manufacturers are aware of the same legislation and brand owner definitions when it comes to tethered closures, how they are interpreting this brief varies. From design capabilities to prototypes and customer feedback, all tethered closures have not been created equal. So what are the possible variations when everyone has the same information? Admittedly, these variations are very small, particularly from a technical perspective, yet this is where the magic happens.

Tiny differences are exactly what matters when it comes to a plastic bottle that a consumer holds up to their mouth; is it comfortable to drink from? Is it easy to open? Perhaps most importantly for the brands, will the consumer buy it again?

Sustainability is of course crucial too, but thankfully this legislation essentially has sustainability built in as standard, with the very purpose of its creation being to support the sorting and recycling of single use plastic packaging. So again, it is the small details that make the difference, both in terms of the volume of raw materials used and the cost of transportation.

Plastic packaging manufacturer RETAL has long engaged its design team to focus on creating a tethered closure solution that ticks all the boxes, from ease of opening to recyclability, and everything in between. Thanks to close connections with its global beverage brand customers, the company is continually working on new iterations of its tethered closures in order to create a solution that meets all the legislative and desirable qualities.

Andzejus Buinovskis, design engineer at RETAL, explains how the widely-available information from the brands means that it is the smallest variations that have the biggest impact. “Clearly it is imperative that all the EU SUP Directive rules of tethered closures, such as all beverage containers of up to three litres must have closures that remain attached, is adhered to, as well as the definitions published by the brands themselves. All manufacturers are working to this same information, and we all have the goal of designing and producing a tethered closure that meets all the criteria and is pleasant to use. The evolving nature of the information makes for a design challenge as well as a design opportunity; I am working on the tiniest changes, but they are crucial. There is a great challenge in knowing that you can only work with certain aspects and that it is your imagination and skill that makes the difference.”

These potentially crucial tiny changes come from the small gaps in the legislation and brand brief; with so much clearly defined and needing to be adhered to, it is in these gaps where designers like Buinovskis must concentrate. He continues, “The precision of the geometry is where we will find success. I work with the 3DExperience CAD programme CATIA from Dassault Systèmes so that I can change minute details and model the variations. The speed between variations can depend greatly; it's easy to get stuck inventing something, but also it's the idea that triggers the variation. It's easy to draw the model when you know what you want, so the most important element is coming up with the invention that meets all the criteria yet is different enough to warrant going through the process of creating a prototype.”

The race is on

These different variations are at the heart of the tethered closure race among plastic packaging manufacturers, which is eased somewhat by the fact that the household name global brands that will be the customers for the closures prefer to have more than one supplier to avoid relying on one manufacturer. Buinovskis adds, “The well-defined requirements from the brand owners are still evolving, so by staying in close contact and carefully listening to their feedback from any prototypes, we can pick up on the minute possibilities for change. The brand owners often conduct testing panels with both experts and regular consumers when a prototype has passed all its existing criteria, so the feedback that comes from these panels is hugely valuable and must be used as inspiration for the next iteration.”

These brand requirements sit on top of the EU SUP Directive legislation, and are primarily concerned with how the tethered closure meets the desired performance of convenience, easy opening, and tactileness. In terms of commercial practicality, Buinovskis explains that RETAL's goal is to create a solution that meets the demands of the major brands and can also be suitable for smaller players in the beverage industry, in order to offer the cost advantage of high volume manufacture. He says, “It is unlikely that a brand will ask for a patent as everyone is working to the same legal requirements, but that is possible. Our goal is to have one tethered closure that is suitable for our whole portfolio of preforms while avoiding any already patented solutions, that we can offer to a range of customers with their own unique variations of colour. We can also offer laser engraving on the inside of the closure for further customisation.”

Why the hold up?

So if all the plastic packaging manufacturers already know the requirements of the global beverage brand owners that will be buying the tethered closures, and the EU SUP Directive legislation that states the legal requirements of the packaging is publicly available, why is there not already an approved solution?  As Buinovskis has said, the test groups of experts and consumers are still in process of analysing the comfort and performance of the proposed solution from RETAL and other manufacturers, so what is clearly defined as a legal requirement, such as the closure 'remaining intact', is not offered as a design solution. Plus, the costs and time involved in each iteration means that what could be nearly perfect is as good as useless. Buinovskis adds, “Our current position is that we are waiting for a metal part to be expertly tooled so that we can create prototypes of our latest iteration; once that is received, we will need to quickly find a small gap in our production, probably at a time when a machine is being adapted for a new colour, so that we can install the metal part in two cavities and then produce a number of samples to be analysed. At each step, our experts are assessing and adapting to make sure every element of the design and production is optimised.”

No going back

What is clear is that tethered closures are not going anywhere. While the marathon-not-a-sprint to design and produce tethered closures that suit beverage brand requirements and meet EU legalities is still in full swing, plastic packaging manufacturers are all working to create their own personal solution so that they stay in the race. But not offering a tethered closure is not going to be an option soon, it's better to be at the front of the pack in order to gain market share. Buinovskis concludes, “It's inspiring to work on a packaging solution that is so focused on sustainability and has such clear rules; the creativity has to be in those minute margins as this is where our advantage lies. I find it motivating to think of my designs of going from such a small scale, where a fraction of a millimeter can make a difference, then to mass production, then to the very personal interaction of a person drinking from a bottle of water...which is then recycled. It's an interesting journey.”