Nanostructured mould tools for plastics
Plastic components are often produced with injection moulding, an established low-cost and high-throughput method. For nano- and micro-scale surface patterning, a variety of chemical techniques are often employed. With EU support of the project PLAST4FUTURE (Injection moulding production technology for multi-functional nano-structured plastic components enabled by nanoimprint lithography), scientists developed a nanoimprint lithography-based method for structuring the free-form surfaces of injection moulding tools and tool inserts made of steel. Nanoimprint lithography is a procedure to form patterns by mechanical deformation. By using moulds and moulding tools with structured surfaces, the manufacturing process is greatly simplified. Further, minimising contamination of raw material with additives such as pigments improves recyclability and significantly reduces energy consumption associated with raw material production. PLAST4FUTURE industrial partners, leaders in their respective fields, developed three highly advanced demonstrators in automotive, lighting and functional toy colouring applications to showcase the technology. Inspired by the wings of butterflies, PLAST4FUTURE technology works by enhancing the lateral resolution on free-form surfaces down to micrometre- and nanometre-length scales. The technology enables functionality of plastic surfaces by topography instead of chemistry. This significantly simplifies the introduction of new products to the market, and safer to produce and use. The patented technology also allows for manufacturing plastic products with functionalised surfaces directly in the injection moulding process, thereby eliminating post-production surface treatment. For one of its demonstrators, the idea behind the PLAST4FUTURE project was to use structural colour that enables plastic production using fewer materials and also facilitates recycling according to a cradle-to-cradle production philosophy. The project team produced a silicon mould with a large array of nanoholes and then moulded the plastic and deposited a thin film of aluminium on top. The result was a coloured plastic without pigments, and the colour could be tuned across the entire visible spectrum by changing the nanohole diameter. Beyond colouring, the project team also investigated how to give plastics antifogging and hydrophobicity features. PLAST4FUTURE provided a manufacturing chain to produce high-value plastic products with functional surfaces by low-cost injection moulding. The technology should greatly simplify the production of nanostructured plastic components for a variety of industries and secure for the EU a large share of a growing global market.
Nanostructured, plastic components, injection moulding, PLAST4FUTURE, nanoimprint lithography