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Four Reasons Why Plastic is Used in Car Manufacturing

Car interior plastics

The use of polymers as plastics in the construction of automobiles has continued to grow over the last decades. Nowadays they are the second most commonly found material in cars.

Here are four reasons why plastic is used in car manufacturing:

  • Plastics reduce the weight of cars
  • Plastics and polymers contribute to the safety of cars
  • Plastics help to lower car manufacturing costs
  • Polymers advance the design of vehicles

To give you a concrete example in numbers: an average modern car weighing 1,500 kg contains about 20% of plastic materials (considering thermoplastics and elastomers). This means 300 kg distributed over 2,000 parts and components of all shapes and sizes.

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Polymers have revolutionised the performance, safety, construction and functionality of cars. Parts made of plastics are resistant to corrosion, offer flexibility and resilience for added safety, have very good thermal insulation, reduce noise and allow optimum space utilization.

So, let’s have a closer look at these four advantages of plastics and polymers for the car manufacturing industry.

Plastics reduce the weight of cars

The primary advantage is that plastics make cars lighter, hence cutting fuel demand and greenhouse gas emissions. For instance, a reduction of 100 kg in the weight of a modern car leads to a reduction in fuel consumption of approximately 0.4 litres per 100 km and in CO2 emissions of around 10 g per km.

Plastics and polymers contribute to the safety of cars

Polymers play a crucial role in car safety. For instance, bumpers made of polycarbonate (PC), polypropylene (PP), Acrylonitrile Butadiene Styrene (ABS), polyurethane (PUR), polyamide (PA) compounded with glass fibers, usually weigh 50% less than those made of alternative materials, while absorbing four to five times more energy during impact.

In addition, durable polyester fibre seat belts, airbags made of high-strength polyamides and plastic child restraint seats have all helped to make cars safer for road users.

Want to know more? Check another article by Simona that looks at how Daimler, one of the largest automotive manufacturers in the world, integrates recycled and renewable plastics in their cars.

Windshields made of laminated glass are shatter-resistant thanks to a thin layer of plastic (typically of PVB or EVAC) sandwiched between two layers of glass, which is lighter and stronger than tempered glass.

Polymers also improve sound attenuation and filter out most infrared rays, thus reducing in-car temperature and consequently the use of air conditioning.

Plastics help to lower car manufacturing costs

Single mould components have helped to manufacture to decrease vehicle assembly time and quickly introduce design innovations at lower costs. A plastic fuel tank made of high-density polyethylene (PE-HD) is inert to the corrosive environments inside and outside of the tank.

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A plastic fuel tank also has a key safety feature: since it can be manufactured as a single part without soldered seams, there are no seams to fail in a collision.

Polymers advance the design of vehicles

Designers and engineers are free nowadays to create innovative design concepts enhancing the functionality of vehicles. Paint protection film (PPF) is a thermoplastic urethane film that is slowly replacing traditional automotive paint on some parts of new cars.

It is 15 times thicker than traditional paint and more resistant to scratches, chips, and UV degradations, retaining a high-gloss shine longer than traditional paint.

Polymers are also contributing to a number of exciting innovations in this field, including key components for electric, hybrid and hydrogen-powered vehicles. New alternative energy vehicles incorporate advances in battery technology using new-generation lithium-polymer batteries that are smaller and run cooler.

They are also used to create fuel cells which power hydrogen cars. As these cars will become more common, the introduction of these technologies will help Europe achieve its 2020 goals of ensuring that 10% of the transport sector must supply its energy needs from renewable sources.