Injection mould specialist SFA Packaging from Middelharnis (NL) is working with Wageningen Food & Biobased Research and three other companies on the world’s first-ever transparent, biobased injection mould packaging. ‘We want to give the consumer a choice’, Niels L’Abée, director of SFA Packaging, explains.

From butter dishes to peanut sauce buckets to salad containers: many foods come in injection mould packaging made of polypropylene.

‘PP packaging is fully recyclable because it is made of just one type of material, says L’Abée. ‘That’s a good start, but a biobased alternative offers a lot more in terms of sustainability, especially if you consider just how much injection mould packaging rolls out of our factory alone.’

Leading the Way

Customers aren’t yet asking for it in vast numbers but, at SFA, they plan to lead the way with a biobased approach.

‘More and more people – not just the government, but also manufacturers and consumers – believe in the need for a more environmentally friendly packaging’, according to L’Abée. ‘We are a major player in injection mould packaging and possess a great deal of knowledge of both the market and the production process. This puts us in a leading position to take on this challenge.’

At a seminar a few years ago, L’Abée struck up a conversation with a researcher from Wageningen Food & Biobased Research. The two of them were of the same opinion that PP packaging could be improved and decided to study the possibilities together. One thing led to another and, since last year, SFA and Wageningen Food & Biobased Research have been together in a public-private partnership.

‘Our aim is to develop biobased packaging that, at a competitive price, emits around half as much CO2 per unit in materials and production as conventional plastics’, L’Abée explains.

The other partners in the project, besides SFA and Wageningen Food & Biobased Research, are machine manufacturer Arburg, injection mould company Hollarts and Rodenburg Biopolymers.

‘Wageningen Food & Biobased Research contributes through its knowledge of and expertise on biobased materials and packaging; we deliver knowledge about the market and production processes.’ The project is partly financed through TKI Agri&Food.

Partners in the Project

Several biobased plastics are already on the market and most are well suited to make plastic films. But using them as the basis for injection mould plastics is an entirely different ballgame. Injection moulding involves ‘forcing’ molten plastic into a mould, which then cools inside of it. It is important that the plastic has the correct flow, or viscosity, during this process.

‘Many commercially available biobased plastics have relatively difficult flow properties by nature. In other words, you can’t simply replace them with conventional plastics. You can overcome this flow issue by making the sides of the packaging slightly thicker but this only means you need a lot more material, which then leads to higher costs and a bigger environmental impact.’ The project partners are studying whether they can improve the flow behaviour of biobased products in such a way that the packaging can maintain a thin wall. ‘We are doing tests with several different raw materials, including PLA and cellulose’, says L’Abée.

In addition, they are seeing if the production process can be improved. ‘The idea is not to close the mould completely while the injection moulding is taking place, but to inject the plastic in first. Only once it spreads out sufficiently do we close the mould.’ The project also focuses on the barrier function of the packaging. ‘You can’t manage this with PLA alone, because it lets too much moisture through. We’re looking for the solution in the use of a label.’

SFA and Wageningen Food & Biobased Research aim to develop a biobased packaging that emits around half as much CO2 per unit in materials and production as conventional plastics.

Scaling Up

The results of the first lab tests are looking good, according to L’Abée. ‘We have tested the material on viscosity, strength and transparency, and we have performed various tensile, drop and impact tests. The packaging passed all the tests with flying colours.’

The partners are now preparing for the next step: scaling up the process to factory volumes. ‘We’ll soon be testing the concept on our own production line’, says the packaging specialist. Besides the flow of the material and the quality of the end product, there are also strict criteria in terms of production speed. ‘A new packaging needs to roll out of the machine every five seconds’, says L’Abée. ‘If the process goes any slower, the costs go up.’

A ‘Green’ Alternative

The project will take around another year to complete. L’Abée hopes that by then he will have a product that is market-ready. He aims to promote the packaging with current customers and attract new customers as well. ‘The price will probably be slightly higher than that of conventional PP packaging. Only time will tell whether the consumer is willing to pay that little bit extra for a “green” alternative like this’, he admits. ‘But I have every confidence.’