Engineering bioplastics for injection moulding

Plastics play a crucial role in our lives. They appear in almost everything we use, from our cars, computers and televisions, to food packaging, toys and leisure goods. Plastics are incredibly useful yet, as society is becoming increasingly aware, are beginning to present a growing environmental threat.

It is estimated that at least 80% of all plastics ever produced have found their way into landfill sites or the natural environment. For example, according to an article in National Geographic magazine, it’s estimated that there are more than 150 million metric tonnes of plastic circulating in the oceans.

Clearly, this situation is unsustainable.

One of the barriers to change is the fact that approximately 90% of all plastics produced are manufactured using fossil resources. The production of plastics currently accounts for between 4% and 5% of all oil consumption globally each year; this percentage is predicted by the World Economic Forum to increase to 20% by 2050.

With growing environmental concerns, associated with factors such as the rising cost of petrochemicals, there is now a growing interest in the use of engineering bioplastics as an alternative material for all forms of plastic moulding and forming, including plastic injection moulding.

What are engineering bioplastics?
The term engineering bioplastic describes a family of materials that are bio-based. They are derived from plants or other biological substances and some, but not all, are also designed to be biodegradable.

In simple terms, bio-plastics are made by converting the sugar found in plants such as sugarcane, cassava, corn or hemp and using this as the basis for the plastic manufacturing process. An alternative bio-source is microalgae, which can be used to create composites by blending microalgal biomass, petroleum, bio-based polymers and additives, or biopolymers such as polyhydroxybutyrates (PHBs).

The most common types of bioplastics are polylactide acid (PLA) and polyhydroxyalkanoate (PHA). Both are now being produced in relatively large volumes around the world

Injection moulding engineering bioplastics
Engineering bioplastics offer a range of critical environmental advantages. They are increasingly being adopted for applications ranging from food packaging to medical devices, and demand is expected to grow by 8% CAGR in the coming years – this is more than twice the rate of growth for petrochemical-derived plastics.

As a leading technical plastic injection moulding company we’re working closely with customers to develop the most effective methods of successfully moulding this new generation of plastics.

In many respects injection moulding engineering bioplastics is no different to other specialised materials. They require careful consideration at both the part design and moulding stages. For example, as some PLA parts can be more brittle, it’s advisable to design rounded corners wherever possible to reduce stress concentrations. Similarly, during the injection moulding process it’s important to manage heat and sheer sensitivity of PLA and natural fibres by adjusting factors such as fill speeds and gate temperatures.

We’ve considerable experience working with a wide range of specialised engineering plastics, including bioplastics. If you’re interested in exploring ways of developing new environmentally-friendly plastic parts, or adapting existing designs, then please get in touch. We’ll be happy to offer advice and guidance.