There are a wide variety of plastics in use within your car, and they are all there for different reasons.

It can sometimes seem as though we live in a world made of plastic, and it can be surprising to discover some of the places that they are used. Plastics are frequently used in car manufacturing, to the point where they are now the second most commonly found materials in cars.

They offer some great advantages to car manufacturers, and have revolutionised how cars have made, which is why their use has increased significantly over the last few decades. They make a difference to weight, performance and safety and help to prolong the life of the car and its various components thanks to its resistance to corrosion.

There are a wide variety of plastics in use within your car, and they are all there for different reasons. Polypropylene is the most popular vehicle plastic as it can be moulded into any shape, whilst polyvinyl chloride (PVC) is rigid and flame retardant. Polycarbonate resists impact and weathering, and acrylonitrile butadiene styrene (ABS) provides a sleek finish for steering wheels and dashboards.

Weight

One of the main reasons that car manufacturers prefer polymers as a material is because of the saving in weight that they offer. If the car is lighter, then it is likely to use less fuel and therefore reduce greenhouse gas emissions. It also means that performance can be increased, as a lighter car is likely to accelerate faster when the pedal on the right is pressed to the floor.

Whilst plastic can make up as much as half of a vehicle’s volume, it only contributes 10% of its weight, so the weight saving can seem immense, and it is hard to imagine another material that can do the same.

Safety

Plastics contribute a huge amount to car safety often because they are able to absorb as much as four or five times more energy during an impact, so they are ideal for parts such as bumpers. There all sorts of plastic polymers in use within a car, including polycarbonate (PC), polypropylene (PP), Acrylonitrile Butadiene Styrene (ABS), polyurethane (PUR) and polyamide (PA).

High strength polymides are used to make airbags whilst durable polyester fibres are the primary ingredients in seat belts. The windscreen in your car might be made of glass but the thing that stops it shattering is a thin layer of PVB or EVAC plastic which sits between two layers of glass. The child restraint seats found in the back of your car have also been made from plastic, and all of this has impacted on vehicle safety in a massive way.

A plastic fuel tank made from high-density polyethylene (PE-HD) is inert to the corrosive elements of the tank, and as it can be made as a single part without seams and joins, it is less likely to fail in an accident.

Cost

Many of the materials used in manufacturing cars can be expensive, and plastics have proved to be an effective way to reduce the cost. Single mould components reduce assembly time and make it much quicker and easier to introduce new design innovations. Most forms of plastics are much cheaper to make and fit than any other alternative, and when a car is less expensive to make, it is also cheaper to buy.

Design

Polymers have given vehicle designers a new sense of freedom thanks to its versatility and flexibility. They have been able to implement new concepts that were not previously possible or were once too expensive. Whether it is a new scratch-resistant paint, alternative forms of power and lighter, cooler batteries, the possibilities now seem endless.

The use of metal on vehicle cladding limits the shapes that can be used. Car manufacturers have therefore switched to plastic to allow much more innovative concepts to come to life. These are also much easier to repair or replace when they have been scraped or dented.

A vehicle’s lifespan is also increased by the use of plastic as it is less susceptible to corrosion caused by salt damage, heat and water exposure. This weather resistance means that a car will keep running for longer, with parts being cheaper and easier to install if they are needed.

Comfort

Plastic has also found some inventive ways to make you more comfortable in your car too. They can both improve the amplification of sound within the car, and they are capable of filtering out a lot of infrared rays, which can stop your car getting too hot in the summer. That’s not to mention the shape of the seat or the grip of the steering wheel and the many other features that we all take for granted every time we get into our cars.

Sustainability

Car manufacturers have long been on a mission to improve fuel consumption, and electric car makers have also made this a big concern. By making their cars as light as possible, they can reduce energy consumption, making their batteries last longer between charges. Many of these EV manufacturers are also moving towards using recycled plastics, resins and bio plastics in an effort to make the entire production and use of their cars more sustainable.

Many of the body panels and internal mechanics are made from plastic components, and even renewable plastic fibres are now in use with some manufacturers making plant-based plastic, sugar-cane derived PET, bioplastics and even caster-oil derived polymides to keep weight down but reduce the harmful impact on the environment.

When it comes to discussing the environment, plastics are usually seen as the enemy, however, in car manufacturing, the opposite is usually true. They can help to reduce emissions and develop the environmental benefits of cars to help ensure that the UK and Europe meet their emissions targets over the next few years.

Plastics have made cars more affordable for manufacturers, and this has been passed down to the consumer, to ensure that more people can get on the road safely and easily. Their use has grown over the years, and thanks to the benefits that they offer, this is only set to increase as car design continues to innovate and develop in new and exciting ways.

About the Author
Nick Mills is the General Manager at Ansini who are specialise in the manufacturing of vacuum formed plastic components for the packaging, automotive and aerospace industry.