Fourty years of stretch film

A bird’s eye view of forty years of development of stretch film: ‘We haven’t finished by any means’

From PVC to PE and LLDPE: over the years, stretch film has developed into a seriously high-tech product. Egbert Kort, Senior Sales Executive at Trioworld, experienced all of these developments up close. In fact from the very beginning: he has been working for our company in Apeldoorn for forty years and can tell you lots about the development of stretch film.

Nowadays, stretch film looks very different from what it was in 1980, the year that Trioworld, as the very first company in Europe, began developing stretch film for use with machines. As Kort knows, it’s been a gradual development of stretch film. In 1980, film was still made from PVC. ‘Today’s film no longer contains any PVC. With PVC we made film that could be stretched up to 60/70 percent. To accomplish this, we first had to heat up the brake rolls.’

The PVC’s successor, PE film, allowed for even more stretch: up to 100 percent. This was followed by LLDPE, Linear Low-Density Polyethylene. ‘A different raw material is used to manufacture LLPDE in comparison to the old-fashioned polyethylene. Today, the stretch standard is 300 percent and our film exceeds this standard,’ says Kort.

700-gram vs 180-gram film

The ability to stretch and pre-stretch is important for making the film thinner. This has always been the goal in order to use less film. Except the motivation now is different. ‘In the past, the main concern was cost,’ says Kort, ‘today environmental considerations also are a major concern.’ At Trioworld the focus has remained unchanged: to create a stable pallet with the least possible film. ‘At the time, a stable pallet required approximately 500 to 700 grams of film. Today we are able to do the same thing with approximately 180 grams.’

This is in part due to the improved quality of the raw materials, as well as the machines and the extruders. The raw material beads are melted in an extruder to be able to make the film. ‘In the past we had three extruders and we manufactured a middle layer, a sticky layer (cling) and a smooth layer. Today, a line has up to nine extruders. In theory this means you can work with nine different types of raw material. All this in combination with our 57 layers. This enables us to produce a much better film.

This was an important development: Trioworld was the first company in the world to produce multilayer films. It makes possible to give each film its own specific properties. For example, one type of film has more longitudinal strength, another has more lateral strength, and still another has high point resistance or high tear resistance. ‘We have different types of film for different product groups. We are often frontrunners in this domain.’

From 3 layers to 57 layers

According to Kort, it’s really very simple. In the past a pallet was not allowed to fall over – and the same applies today. ‘A pallet must always arrive at the customer in good condition. However, the standard has become more strict because, for example, the Albert Heijn supermarket chain has a fully automated warehouse and is therefore more critical. However, the required stability has not changed in all these years.’

Stability is therefore important for the final journey at the customer, but also for safety during transport. Unstable pallets can shift, with all of the attendant potential consequences. Research shows that each year, approximately four percent of all transported pallets become damaged. This not only entails additional costs, but also waste. Preventing damage is a priority for Trioworld, in part because of the sustainability aspect. ‘We were always able to create a stable pallet, but today we can do that with less film,’ says Kort.

But how is it that with thinner film you can still achieve pallet stability? By maximally stretching and wrapping the film, Kort explains. ‘With the arrival of better extruders, we were able to go from 3-layer to 5-layer, 7-layer and 24-layer film. Today we have a 12-micron film with a maximum of 57 layers. It truly is a technical feat; film is a super high-tech product.’

More stretch

To be able to stretch the film even further, the wrapping machine must do more than just wrap: it must be possible to adjust the machine better and more accurately. ‘In the past the machine simply went up and down, but today it is capable of doing much more. You can indicate where you need more stretch or additional wraps. That makes everything more complex.’

Trioworld has been coordinating the machines’ operation with the film since the eighties. ‘This is why we have a great deal of experience with different machines. For example, we precisely understand the relationship between the machine and the different films,’ Kort explains. ‘There is no stretch film seller education programme. We train our new colleagues internally. It’s all about knowledge transfer within the organisation and keeping up with new developments.’ As a result, all Trioworld’s technical engineers know how to configure a machine so as to create a smooth wrapping process that furthermore fosters uptime.

Price per wrapped pallet

And this is where Trioworld’s added value comes in. This Dutch company in Apeldoorn distinguishes itself from the competition through its knowledge of machines and materials. ‘This knowledge is needed to enable the machine to perform optimally,’ says Kort. ‘I regularly visit companies that have a high-quality machine and film, but where neither is fully exploited. It’s like having a Mercedes, but you never drive faster than 80 km/hour. We try to configure the machine in the best way possible so that you end up with a more stable pallet, while using less film. Other companies check to see which roll performs best on their machine and then the key issue is often about price per kilo of film. We speak about the price per wrapped pallet, because ultimately this is what it’s all about.’

As mentioned earlier, one of the benefits of a smoothly running process is improved uptime. An optimally wrapped pallet translates into greater safety and reduced costs. This is what it’s all about, as Kort puts it: achieving the lowest possible TCO for the customer.