Plastics and Polymer Composites in Light Vehicles
Light vehicles represent an important market for plastics and polymer composites, one that has grown significantly during the last five decades. The average North American light vehicle now contains 351 pounds of plastics and polymer composites, 8.8% of the total weight. Although this is off from the prior peak in 2009, it is up from 343 pounds in 2010, 279 pounds in 2000 and 156 pounds in 1990. In 1960, less than 20 pounds were used. The typical light vehicle may contain over than 1,000 plastic parts.
Long-Term Trends in Light Vehicle Plastics & Polymer Composites Use (pounds/vehicle)
Composites are any combination of polymer matrix and fibrous reinforcement. Glass, carbon, aramid, and other fibers provide strength and stiffness while the polymer matrix (or resin) of polyester, polyurethane, epoxy, polypropylene, nylon, or other resin protects and transfers loads between fibers. This creates a material with attributes superior to polymer or fiber alone. In recent years, carbon fiber-reinforced composites have made inroads into light vehicle applications.
Plastics and polymer composites have been essential to a wide range of safety and performance breakthroughs in today’s cars, minivans, pickups and SUVs. Today’s plastics typically make up 50% of the volume of a new light vehicle but less than 10% of its weight, which helps make cars lighter and more fuel efficient, resulting in lower greenhouse gas emissions. Tough, modern plastics and polymer composites also help improve passenger safety and automotive designers rely on the versatility of plastics and polymer composites and the aesthetic possibilities when designing today’s vehicles. In addition, many plastic resins are recyclable.
Automotive Body Exterior –Plastics and polymer composites have revolutionized the design of body exteriors. From bumpers to door panels, lightweight plastic provides vehicles with better gas mileage and allows designers and engineers the freedom to create innovative concepts that otherwise would be impossible. In the past, metals were synonymous with auto body exterior design and manufacturing. They are, however, susceptible to dents, dings, stone chips and corrosion. They are also heavier and more expensive than plastics. Specifying plastics and composites for automotive body exterior panels and parts allows manufacturers to adopt modular assembly practices, lower production costs, improve energy management, achieve better dent resistance, and use advanced styling techniques for sleeker, more aerodynamic exteriors.
Automotive Safety – The versatility of plastics allows design options that reduce vehicle weight while producing safer vehicles. Included are plastic composite structures in the front end of a vehicle that reduce vehicle weight without compromising safety and plastic components in crumple zones that help absorb energy while lowering vehicle weight. Plastics are also used in door modules to maintain or improve side impact safety, plastic layers in automotive safety glass prevent passenger injuries, and plastic foams can add strength to automotive body cavities and increase occupant safety in vehicles.
Automotive Electrical Systems – Over the last 20 years, the electrical systems of light vehicles have undergone a major revolution. Automotive electrical and electronic system components are now more numerous and important with computer chips regulating and monitoring ABS brakes, fuel injection, and oxygen sensors, GPS navigation equipment, obstacle sensors, state-of-the-art audio systems, and other systems. Plastics make possible the inclusion, operation, interconnection and housing of sockets, switches, connectors, circuit boards, wiring and cable, and other electrical and electronic devices.
Automotive Chassis – A chassis is the supporting frame of a light vehicle. It gives the vehicle strength and rigidity, and helps increase crash-resistance through energy absorption. The chassis is especially important in ensuring low levels of noise, vibration and harshness (NVH) throughout the vehicle. Not only does a reduction in NVH allow for a more pleasant driving experience, but by putting less stress on connecting components it can help increase the life span of these components. The key determinant permitting reduced levels of NVH is energy absorption. As a result, passenger protection can be enhanced in the event of a collision. Plastics are making inroads into the chassis market. Innovations in plastic technology have brought about the development of successful chassis applications and structure, support and suspension performance.
Automotive Powertrains – The powertrain is one of a light vehicle’s most complicated parts. The term “powertrain” refers to the system of bearings, shafts, and gears that transmit the engine’s power to the axle. Included are composite drive shafts that increase torque. Plastics help reduce the number of parts needed to assemble these complex components. Plastics also help reduce vehicle weight, which helps lower assembly costs while increasing fuel efficiency. For example, the utilization of lightweight plastics in a vehicle can allow manufacturers to utilize smaller, lighter weight engines.
Automotive Fuel Systems – For automotive fuel system components, plastics have several advantages that enable it to outperform metals. Plastic frees engineers from the design constraints that metal imposes. Plastic’s light weight makes vehicles more fuel-efficient and from a safety standpoint, rupture-resistant plastics with high impact strength are helping keep automotive fuel tanks and related delivery systems leak-proof, corrosion-resistant, and reliable.
Automotive Engine Components – Many of today’s automotive engine components are plastic. From air-intake manifolds and systems to cooling systems to valve covers and other engine parts, plastic helps make engine systems easier to design, easier to assemble, and lighter in weight. Plastics’ versatility has revolutionized automotive engine component design.
Automotive Interior – The elements of automotive interior design — comfort, noise level, aesthetic appeal, ergonomic layout, and durability — have a great effect on a consumer’s purchasing decision. Plastic automotive interior parts address all of these aspects, and more, in a remarkably effective and efficient manner.
The automotive market is an important market for plastic resins such as nylon (polyamides), other engineering polymers, and thermoplastic polyesters. Light vehicle applications often account for over 30% of the demand for each resin. Other resins include ABS and polyvinyl butyral. For the latter resin which is used in safety glass, the automotive market accounts for over 85% of total demand. Engineering polymers such as nylon, polycarbonate (and polycarbonate blends) and others are supplanting metals in many applications. Typical plastics and composite applications include exterior panels, trim, and bumper fascia, as well as interior trim panels, window encapsulation, headlamp housings, manifolds and valve covers, electronic/electric parts and components, wiring harnesses, steering wheels, insulation, dampening and deadeners, upholstery, mechanical parts and components, safety glass, and myriad other uses.
Average plastics and composites per vehicle use increased three pounds (0.9%) to 351 pounds in 2018, and plastics and composites maintained its share of the overall weight of a typical vehicle. Over 15 major resins find significant use in light vehicles. Details on resin use are presented in Tables 3 and 4. Major polymers used in light vehicles include on average 84 pounds of polypropylene (PP), 63 pounds of polyurethanes, 43 pounds of nylon, 22 pounds of polyvinyl chloride (PVC), 20 pounds of acrylonitrile-butadiene-styrene (ABS), 17 pounds of polyethylene resins, and 17 pounds of polycarbonate resins.
Polypropylene (Click thumbnail to left for full chart of primary polymers in automotive markets) is also used in thermoplastics polyolefin elastomers (TPO) and its use in that area is reported separately under rubber. Average TPO use is nearly 35 pounds per vehicle and if it were included in plastics and polymer composites the total would be the equivalent of over 385 pounds per vehicle.
Note: Polypropylene is also used in thermoplastics polyolefin elastomers (TPO) as well but its use in that area is reported separately under rubber in Table 2. TPO use averages nearly 35 pounds per vehicle. Polypropylene resin applications include interior trim, under-the-hood components, HVAC components, battery cases, and other OEM uses.
Over the last two decades, other engineering resins such as polyacetal, polyphenylene ether (PPE), and thermoplastic polyester engineering resins have supplanted metals in a number of applications. (Click thumbnail to right for full chart of Average Large Volume Plastics Content of North American Light Vehicles (pounds per vehicle)) Average use of these resins was 39 pounds in 2018, up from 38 pounds in 2010, 30 pounds in 2000, and 18 pounds in 1990. Polycarbonate and nylon are also classified as engineering resins (as are some ABS grades) and if polycarbonate and nylon resins were included, total engineering resin consumption would be 99 pounds. An average of seven pounds of polyvinyl butyral are used. Additional resins such as acrylics, phenolics, unsaturated polyester, and others account for the remaining 36 pounds.
Additional opportunities to reduce weight with plastics and polymer composites are possible. (Click thumbnail to left for full chart of Average Engineering & Other Plastics Content of North American Light Vehicles (pounds per vehicle)) These include: 1) reducing the weight of existing plastic and composite parts with the use of low density additives, nanoparticles, and alternate fibers; and 2) converting more metal parts to plastics and composites. Furthermore, industry mega trends for future mobility, including self-driving vehicles and ride-sharing platforms will create numerous unique opportunities for plastics and composites due to increased safety requirements and new vehicle architectures. As a result, the light vehicle market presents significant opportunities for further diffusion of plastics and composites in the future.