Safer and greener plastics – new recyclable compounds for consumer products

As world markets expand, especially in developing countries, the need for new materials to satisfy production requirements continues to grow. At the same time, high oil prices push up the costs of petroleum derivatives such as polymers, in other words, plastics, used in innumerable consumer items.

One recent and very interesting line of research in the field of materials involves the combination of natural fibres with thermoplastics. Wood, flax, hemp and jute are just some of the natural materials now showing promise in this sort of use.

Partners in the EUREKA FACTORY ECOPLAST project decided to join efforts to develop a palletised compound suitable for injection moulding and extrusion processes, combining two or more material components in such a way that the resulting compound is better than any of the individual components alone.

“We need to develop new materials that are cheaper and better,” says FACTORY ECOPLAST coordinator Uros Znidaric of Slovenia’s ISOKON. “Ideally, such materials should also be more easily recyclable, reducing environmental impact.” Project partners looked at compounding conditions, palletising processes, deformation properties, compatibility between natural fibres and thermoplastics, injection moulding parameters and possible applications.

“Once we had enough information about different compound properties, we then focused on product selection,” says Znidaric. Final selection was based on key properties, including rigidity, weight and price. The ability to saw and drill the material was also considered, as well as wear and tear on machine equipment used in processing final products.

“The project was very successful,” says Znidaric. “We were able to define precise technological parameters for extrusion and an optimal palletising process for making compounds for injection moulding and extrusion. The new materials are suitable for use in the manufacture of a wide variety of products, including vacuum cleaner and lawn mower parts, storage boxes and even golf tees.”

Sounds good

Acoustic properties also became a focus of investigation. Znidaric explains, “Although wood is known for its good acoustics and is often used in musical instruments, today a lot of speaker boxes are made of injection-moulded polymers. We wanted to see if our new composite, which contains wood, might display better acoustic properties.”

FACTORY ECOPLASTIC results show that the wood fibre-filled composites developed under the project are indeed well suited to use in loudspeaker boxes. Znidaric says both damping of sound radiation and sound wave resistance for the material are comparable to those displayed by medium density fibreboard (MDF), one of the most commonly used materials in this application.

Further tests of the project’s new ‘EUREKA’ speaker boxes show higher frequency acoustic performance on a par with market leaders such as JVC and Nakamichi. The potential for FACTORY ECOPLASTIC commercialisation, say partners, is therefore very high.