| What is it about plastics objects that catches our attention? Its shape? Its usefulness? Its colour? Plastics are coloured using two main methods. The surface can be painted or printed after moulding, or additives called PIGMENTS can be incorporated before or during moulding. With this method, colour pigments can create all sorts of decorative effects that go all the way through the object and of course, will never wear off. This property, coupled with the range of moulding techniques available, gives designers today a tremendous freedom when working with plastics. Pigments are tiny particles which have to be evenly mixed into the polymer in its molten state. Colourists specialise in scientifically devising shades suitable for all types of situations. Through a skilful manipulation of additives, plastics components can be colour matched with parts made from other materials such as wood, metal and fabrics, cars radios and kitchen appliances all use this technique.
Different pigment formulations co-ordinate plastics with other materials, as in the Land Rover Discovery (BASF). Fashion is a word that not only covers clothes and accessories, but also includes, tableware, kitchenware and office equipment. In all these areas, pigments enable plastics to offer an endlessly variable palette of colours, as vivid as any other media. Colour in plastics also has many non-decorative functions. It can be used to cut down light to protect the contents of a package, for example in medicine bottles. It can be used as an important danger signal. Often it is used simply to protect and conceal, as in dashboards, machine housings and pipes. To make an opaque moulding, pigments are chosen that absorb or scatter light very well. The most common, cost-effective way of creating solid colour is to use carbon black or titanium dioxide. Carbon black absorbs light, whereas titanium dioxide, with its high refractive index, scatters light, producing a very high level of whiteness and brightness. It is part of a range of inorganic pigments and is mixed with other colours to create pastel shades. Organic pigments are also good for making bright colours. |