The packaging industry is under pressure to offer more sustainable solutions and is therefore looking to plastics suppliers to provide an alternative to traditional fossil fuel based plastics. From soft-drink cups at fast food restaurants and festivals to fresh fruit and vegetable containers: the packaging industry is no stranger to biobased polylactic acid (PLA) plastic. Made from natural, renewable resources such as sugar cane or corn, PLA provides packaging producers with a reliable, biobased solution that can be recycled or composted after use. So far these biobased plastics have largely been limited to cold food packaging and disposable applications.
New application possibilities include fast-food clamshells. (photos: Purac)
The performance properties of today’s commercially available PLA are sufficient for applications such as disposable plates and cutlery, shopping bags and low heat packaging. Until PLA could successfully withstand use temperatures in the range of 80°C to 120°C, the application possibilities remained limited. Purac, a Dutch lactide producer with 80 years of experience in lactic acid production, has developed a heat resistant PLA technology that could open up vast market potential as a biobased replacement for polystyrene (PS) and polypropylene (PP).
Cups made from Puralact are able to contain boiling water without any sign of distortion. (photos: Purac)
Overcoming high temperatures
Over the last decade, Purac’s R&D efforts were focused on the development of high quality lactides for PLA. The team worked on developing PLA homopolymers with performance qualities to rival some of the most established and trusted plastics in use today. PLA based on “Puralact” lactides can withstand temperatures of up to 120°C, making it suitable for applications such as hot food and beverage containers. Cups made from Puralact are able to contain boiling water without any sign of distortion. It has also been approved for food contact use.
New application possibilities include fast-food clamshells.
François de Bie, Marketing Director at Purac Bioplastics says: “In order to unlock PLA potential for the packaging industry as a whole, we needed to deliver a new level of PLA performance. For us, this started with the development of stereochemically pure L and D lactide. The resulting PLA homopolymers were far more resistant to high temperatures and impact, which creates opportunities for product developers seeking a biobased solution for high temperature packaging applications.”
Instant noodle pots can now be biobased thanks to Purac’s high heat PLA technology.
The result can be seen in the company’s biobased PLA used in high heat applications, such as cups in hot drink vending machines for example. The biobased PLA coffee cups can hold boiling water without any form of distortion,” claims de Bie and continues, “We are removing the previous barriers that restricted packaging producers from working with biobased plastics, and opening up opportunities for 100% biobased products.” New application possibilities include microwave meal packaging, hot beverage cups, soup tubs, noodle pots, fast-food clamshells and disposable plates, bowls and cutlery. “Single-use instant noodle pots can now be made from biobased plastics. Using Purac Puralact based PLA, the thermoforming process typically used to produce these pots can run at almost the same speed as the traditional PS thermoforming process. And, of course, PLA can also be used to make injection moulded parts.”
François de Bie, Marketing Director, Purac Bioplastics
Infrastructure: recycling
PLA is a recyclable material, which Purac demonstrated in their recent cooperation with the Perpetual Plastics Project, an initiative created by former Delft Technical University (TU Delft) students. The project created a ‘do-it-yourself’, interactive ‘machine’, which provides users with a small-scale demonstration of ‘how easily PLA can be recycled’: following the steps of cleaning, drying, shredding, melting and extrusion, before finally remade into a new article by a 3D printer. PLA drinking cups were provided by Purac and Groenbeker for use – followed by immediate manual recycling – at both large and small events.
“How easily PLA can be recycled” (video: Purac)
According to François de Bie, this is an important stage in the PLA lifecycle, which needs to be addressed sooner rather than later. “Although PLA is still a relatively new material to the plastics industry, it promises to become widely implemented throughout a broad range of applications. It is therefore vital that we already start to think about how best to recycle these valuable materials.”
The current recycling industry is awaiting a more substantial stream of PLA material before adapting their existing recycling capabilities. This is a logical course of action, according to de Bie: “We are at the early stages of PLA implementation, and it therefore makes sense that there is not a lot of material to recycle yet. At present, the most important aspect to convey is that PLA can be easily recycled. Once the material is widely implemented, the resulting waste stream will attract recycling firms to receive this valuable material as building blocks for new applications.”
Purac is continuously exploring new application areas for high performance PLA and are collaborating with a number of co-development partners.
www.purac.com/bioplastics
