PVC, plasticised with phthalates, has doubled the life of modern cars. It makes vehicles safer for drivers and passengers alike and, at the same time, underlies advances in the quality, cost-effectiveness and comfort of vehicles which we often take for granted on the road.
The average car has today more than 1,000 plastic components and roughly 12 % of them are made of soft PVC. Vehicle manufacturers clearly recognise the design, weight and cost benefits of this material used mainly as underbody coatings and sealants, wire harnesses, passenger compartment parts and small exterior trims and fittings.
The use of soft PVC in protective layering for the chassis has doubled the average life of modern vehicles and drastically reduced the need for servicing and repairs. In order to make this protective layer, high phthalates are combined with PVC to produce a liquid paste known as plastisol. The latter is sprayed onto the metal underbody where it solidifies into a thin but extremely tough surface whilst the paint dries, helping to protect the chassis against grit (stone-chipping), dirt and water and thus minimising corrosion. The lightweight coating does not increase the petrol consumption of the car and requires no further servicing. As it is sprayed on, all metal parts are equally protected, even those which are recessed.
Soft PVC makes modern vehicles safer and more reliable. Electrical wires covered with flexible PVC sheathing are strengthened to resist shocks from the road whilst retaining the flexibility to withstand continuous mechanical stress, coping with the many sudden movements to which vehicles are subjected.
For heat resistant wires around the engine, specialty plasticisers, such as high phthalates with a carbon chain above 10 and/or trimellitates, can be used to impart increased resistance to high temperatures. These PVC cables have to be able to withstand heat when the engine is running and, at the same time, resist cold when, for example, the vehicle is left outdoors in winter.
Image courtesy of Vulcaflex
Plasticised PVC plays a critical role in reducing injuries and enhancing the appearance of cars. PVC dashboards, for example, cushion impact in accidents. Very often in luxury cars, the instrument panel is covered with a flexible PVC skin to look and feel like leather while retaining all the safety advantages of the polymer and offering increased resistance to scratches. Cars are also quieter now thanks to the sound-dampening properties of soft PVC.
The versatility of the material enables manufacturers to achieve exact size, shape and texture specifications for door panels, arm rests, sun visors, rain strips and other small parts. Soft PVC is able to meet the challenges presented by difficult shapes much easier than alternatives, both in cost and quality.
Externally, soft PVC protects vulnerable areas such as doors from small impacts and scratches. It is found in body side protection strips, weather strips and window sealing profiles. Thanks to high phthalates, the degree of softness of these parts can be determined precisely in order to enable them to resist to and release physical stress.
PVC and high phthalates offer unbeatable cost-effectiveness as they help to make vehicles more affordable. For the environment, the lightness of soft PVC parts helps to reduce the weight of vehicles which, in turn, lowers wear and tear on roads at the same time that it decreases fuel consumption.