Dual cure technology for thermoformable coatings in automotive interior applications

摘要

Ever since the thermoforming process,developed at the end of the 1950s,was first considered as a low-cost method for creating prototype substrates,it has been further refined during the last 50 years to become a widely used method for producing large quantities of commercial-grade products.Today,thermoformed plastics are used in the manufacturing of many structural and functional plastic parts,including automotive body parts,consumer electronic devices and household appliances.In the thermoforming process,thermoplastic materials,such as PET,PC,PMMA and ABS,are heated above their glass transition temperature and become soft and flexible.A mould is then pressed onto the substrate.Once it has cooled and solidified again,a 3D piece is formed.A disadvantage of commonly used thermoplastic materials is that they do not have a good scratch or chemical resistance.Therefore,a spray coating is often applied on the formed pieces.Some drawbacks of this process include the need for expensive paint shops,waste of product by overspray,long oven drying and surfaces sensitive to paint defects.A solution to circumvent those shortcomings is to apply a thermoformable coating before the forming,rather than after.That way,the complex lacquering of three-dimensional substrates is replaced with a much simpler and higher yield coating process of flat substrates with a thermoformable coating.These precoated substrates can then be formed,trimmed and if needed back injection moulded by the converter.