Plastic coatings: “Increased use in automotive”
What are the advantages of plastic coatings over other substrates?
Dr Markus Mechtel: For a long time, polyurethane coatings have proven their value in different applications and on various substrates, including plastics. For instance, they offer a number of advantages over uncoated thermoplastic materials, e.g. high gloss and protection of the plastic substrate. We even offer raw materials for self-healing coatings. A new development is “DirectCoating” technology, by means of which coated components can be injection moulded efficiently in a two-component mould.
Through developments such as this, we are supporting the growing usage of plastics in automotive construction. Plastics lower the overall vehicle weight, and that in turns leads to lower fuel consumption and a greater range for electric cars.
Which raw materials are the most suitable for automotive plastic coating, are there any new developments?
Dr Markus Mechtel, head of automotive marketing at Covestro.
Mechtel: Polyurethane coatings are an ideal choice for both automotive interiors and exteriors due to their customisable properties. We offer a whole range of raw materials for primers, basecoats and topcoats. A recent development is the innovative “Blulogiq” technology for the efficient coating of exterior plastic parts at low temperatures. Even though curing is as much as 30 percent faster than with conventional two-component coatings, the appearance is still very good. At the heart of the technology is a thermolatent hardener which makes it possible to separate film formation from curing. In the medium term, this technology will make it possible to coat plastic, composite and metal automotive parts together for the first time.
Do environmentally friendly raw materials play a role in plastic coating?
Mechtel: Environmentally friendly, water-borne PUR coatings are already widely employed in car interior applications in Europe, including soft-touch coatings. As further advances are made in electric mobility and renewable energy sources, we expect growing demand for a reduction in the carbon footprint, such as can be achieved with, for example, bio-based coating raw materials. We have anticipated this trend by developing a bio-based hardener for polyurethane coatings. The bulk of its carbon content – 70 percent – is derived from biomass. The product delivers the same high performance as conventional, petrochemical-based isocyanates, and perfectly complements the new polyols and resins currently being developed with the aid of renewable materials.