By Bruce Geiselman
Automobile manufacturers and parts suppliers increasingly are adopting plastic parts to help meet evolving regulations and consumers’ and shareholders’ demands for sustainability and improved environmental performance.
The federal government, by tightening Corporate Average Fuel Economy (CAFE) standards, is encouraging automakers to reduce vehicle weight in internal combustion engine (ICE) vehicles. At the same time, as the government and automakers are striving to encourage consumers to buy electric vehicles (EVs), automakers are trying to trim part weight. Plastics are playing a key role in those initiatives.
Mubea: Leaf spring demonstrates possibilities
One company that’s had success lightweighting vehicle parts is Tier I supplier Mubea, which, along with General Motors (GM), was honored last year as the Grand Award winner of the Society of Plastics Engineers’ Automotive Division’s 51st annual Automotive Innovation Awards competition.
Mubea developed the first all-composite leaf spring for light trucks — a part that GM uses in its 2022 Chevrolet Silverado and GMC Sierra light trucks. Consisting of about 60 percent glass fiber by volume, the part is created through compression molding.
The part reduces mass by up to 75 percent compared with all-steel construction and 58 percent compared with hybrid steel/composite leaf springs. It twice as durability, improves ride comfort, lowers noise and vibration, and increases payload, according to Mubea. Also, unlike metal, it can’t corrode. Fiberglass-reinforced epoxy prepreg is used to form a single leaf with a progressive spring rate that eliminates the shackle and shackle bushing.
Mubea had developed a similar technology for composite leaf springs for use on commercial vans in Europe, before bringing the idea to U.S. light truck makers.
“GM was particularly interested and almost immediately started funding basically an R&D program to work through the implementation hurdles that we might see while adapting this to the North American truck market, since the whole situation is a little different for consumer pickup trucks in North America versus a commercial van in Europe,” said Jared Heitsch, engineering manager for Mubea’s chassis composites business unit in North America.
Mubea is a long-time supplier of parts for chassis and body components to automakers but began working with plastic composites only within the past 15 years.
The automobile industry is increasingly facing conditions that favor the use of lightweight, durable plastic composites.
“This is kind of an interesting time in the marketplace,” Heitsch said. “With EVs, there’s a lot of push for lightweighting because the batteries are extremely heavy. If you’re looking at a similar-size vehicle, you’re seeing pretty shocking numbers for how heavy the BEV [battery electric vehicle] version of a similar-size vehicle can be [compared to an ICE vehicle].”
At the same time, ICE vehicles need to meet increasingly strict fuel economy standards.
“Basically, we’re in a situation where there is significant cost savings as a whole to GM for implementing our springs because they’re able to reduce the weight of some of the vehicle variants, which drops them down into different weight classes. This dramatically reduces their greenhouse gas penalty costs, basically, that they would have to pay to the government. Essentially, they get a lighter-weight vehicle that performs better, customers are happier with because there is less noise and there is improved ride quality, and they save money by using it. It’s a win-win all around on those,” Heitsch said.
Another reason for switching from metal to plastic parts is to improve sustainability and decrease greenhouse gas emissions during manufacturing.
“For something like a leaf spring, which is traditionally a 60-pound steel part, there are tremendous amounts of carbon emissions required during the mining, the refinement and the production process for that part. The footprint is much smaller for a composite part that can replace that. As more companies strive to reduce those emissions, it’s kind of a no-brainer if you can take something like a 70 percent reduction in carbon emissions by switching from a steel part to a composite part in the same application.”
Ineos Composites: Value efficiency is key
Dan Dowdall, a business development manager for resins manufacturer Ineos Composites, said it remains to be seen what the transition from ICE vehicles to BEVs will mean for plastics businesses.
“We’re trying to digest it, and certainly change or adjust our business accordingly,” said Dowdall, who has been in the business for 35 years. “From my perspective, I think the OEMs have always had key priorities, and they’re just shifting a little bit. Some of it is good for plastics, and some of it maybe is not so good for plastics.”
A part of the Ineos Group, a British petrochemical company, Ineos Composites sells resins to many Tier I suppliers as well as smaller compounders. Its resins are used extensively in exterior body panels, pickup truck beds, EV battery enclosures and front-end trunks.
The No. 1 priority for OEMs continues to be value efficiency, Dowdall said.
“They’ve been screaming for lower-cost products forever, but I think now as EVs come on more, they bring a lot of cost with them,” he said. “It’s even more important for the OEMs to try to find offsets to the cost of these batteries and motors and everything else.”
Dowdall also sees new opportunities for plastics with products for EVs that didn’t previously exist.
“Our business particularly is seeing a lot of growth in frunks, as we call it, or front trunks,” he said. “Because they’re big parts, they lend themselves well to plastics and composites.”
Another growing area is plastics for battery enclosures. In addition, OEMs are interested in body panels into which sensors and components for sensors and autonomous vehicles can be embedded.
“Vehicles are just full of sensors and electronics right now,” Dowdall said. “They can be attached or molded in the plastic parts with a lot more ease and provide advantages.”
While EVs are presenting some new opportunities for plastic parts makers and resin suppliers, there are some negatives, Dowdall said.
“As the world moves to 30 percent electric vehicles, or 50 percent, we’re going to see a lot less engine covers and intake manifolds and radiator supports — some of the traditional areas where plastics has had a dominant position. They’re going to start going away. So, it’s good that we’re finding new applications to replace that business.”
Teijin Automotive Technologies: Lightweight and heat-resistant
Tier 1 supplier Teijin Automotive, which develops and produces advanced composites and components, is focusing on the needs of the automotive industry with advances in two areas: covers for batteries for EVs and lightweighting.
The automotive industry’s transition to BEVs is “a tremendous opportunity,” said Hugh Foran, executive director of the Advanced Development Center for the company, which makes sheet molding compound (SMC) resins, body panels and pickup beds for Toyota, Honda and other manufacturers.
One of the fastest-growing areas for Teijin Automotive is producing resins for battery boxes and battery boxes for EVs.
“We have currently four formulations that are specific to battery cases — the covers and the trays,” Foran said.
- Teijin’s base grade is vinyl ester SMC grade with 50 percent glass for battery boxes that don’t need special thermal properties.
- A high-fill polyester/vinyl ester aluminum trihydrate is available for battery boxes and applications that require fire resistance.
- An intumescent grade of thermoset composite “scabs up like your body” to protect itself from heat during a fire involving batteries, Foran said.
- A phenolic resin — similar to the original Bakelite (invented in the early 1900s) — offers higher thermal resistance than aluminum.
In addition to the four basic formulations, Teijin is working with individual automakers to make resins and battery boxes specific to their needs. For example, weights of battery packs can vary significantly, so the amount of glass or carbon fiber in a resin blend can vary.
Increasingly, automakers are incorporating battery trays and covers into vehicles interiors. In some cases, battery covers serve as the floors of the vehicles, providing additional weight reductions.
“It [the battery cover] actually has the seat mounts and the center consoles, and it’s an actual part of the vehicle itself,” Foran said. “It’s not simply a battery cover, but it actually has all the components, so, when they bring it up into the vehicle, the carpet is there, the seats are there, the seat belt mounts, the center console is there, and it is actually more a part of the vehicle than just something that they bolt on after the fact.”
Another weight-reduction strategy Teijin is promoting involves the use of its Hexacore cellular core and Foam-A-Core foam core technologies for lightweighting composite body panels.
“We can mold very thin outer panels, and then they're supported by a cardboard or a foam core to give it the structure that it needs,” Foran said. “We're actually molding parts at a millimeter and a quarter thick, which is very thin for a composite panel. Previously, all the panels that we’ve been building have been around 2.5 millimeters thick. So, that does two things for us. It reduces the cycle time for curing, and it reduces the weight.”
SABIC: Materials address multiple demands
“I think this is the most exciting time for anyone associated with the plastic industry, whether it’s the material manufacturers or Tier 1 manufacturers or anyone who is working in a plastic industry,” said Dhanendra Nagwanshi, global automotive leader, EV Batteries & Electricals, at SABIC Petrochemicals.
Conventional materials, like steel and aluminum, have limitations as automakers are transitioning from ICE vehicles to EVs, and plastics can address many of those limitations, he said.
As part of its Bluehero platform, designed to accelerate the world’s energy transition to electric power, SABIC has been developing new flame-retardant materials for use with EV batteries.
In an aluminum battery enclosure, flames can melt through the metal, endangering occupants of an EV. However, in laboratory testing, a battery lid manufactured with SABIC’s new Stamax FR resin prevented flames from breaking through during a 5-minute exposure. When the material comes into contact with intense heat, it forms char or an intumescent layer that is hard and stiff and prevents flames from penetrating the battery enclosure. Despite a 2,012-degree Fahrenheit flame on one side of a composite battery lid manufactured with Stamax FR, the temperature on the other side of the lid reached a maximum of only 392 degrees Fahrenheit, Nagwanshi said.
Using Stamax FR resin for a battery cover in place of aluminum can eliminate the need for a thermal blanket, reducing cost and weight, Nagwanshi said.
Honda made an EV battery pack cover for its CR-V model in China with SABIC’s flame-retardant PP compound. With the short-glass-fiber material, the EV needed no thermal blankets to comply with China’s EV fire safety requirements. The part reduced part weight by 40 percent versus a similar design in metal, according to SABIC.
Also, Nagwanshi said, “Recently, our CEO announced that by 2030, SABIC is committed to have 1 million [metric] tons of circular products.”
SABIC’s TruCircle solutions will include materials produced at the company’s first commercial advanced recycling plant in Geleen, Netherlands. In January, the plant was in the final stages of construction. It is expected to deliver its first commercial polymers this year.
Solvay: Making engines smaller, more efficient
Solvay, a Belgian multinational chemical company with operations in the United States, is developing plastic resins that can improve the efficiency of EVs.
“Most of those opportunities are coming within the electrified powertrain,” said Brian Baleno, head of marketing-automotive for Solvay. “We define the electrified powertrain as the battery system, the power electronics, commonly known as the inverter, and the electric motor. More and more, they’re demanding higher-performance materials within each of the systems, and that’s where we’re putting a lot of our research and development efforts.”
Solvay is developing plastics with greater chemical resistance as automakers use different cooling fluids and media to cool electric motor systems, Baleno said. Automakers also want better and higher-performing materials as they look to miniaturize components and use less material to make them.
Solvay is developing solutions that allow automakers to scale down the size of motors while increasing efficiency.
For example, magnetic wire insulation has typically been made from a polyamide-imide (PAI) material, but Solvay's KetaSpire polyetheretherketone (PEEK)-based material offers superior insulation properties, as does its slot liner film made from PEEK, Baleno said. The Solvay materials are thinner with more thermal conductivity and allow for greater copper wire slot fill, which maximizes the motor’s power output.
“In the process of doing those two things, you make the electric motor more efficient, and by making the electric motor more efficient, you can actually downsize the electric motor, as well as downsize the battery because you have a more efficient electric powertrain,” Baleno said.
Solvay also is developing plastics, including new grades of polyphthalamide (PPA) and polyphenylene sulfide (PPS), that can withstand higher temperatures for use in an electric motor’s traction inverter.
As Solvay is developing new materials to meet the needs of EVs, it also is working on making the materials more sustainable.
“In the case of PPA, we’ve reduced the GWP [global warming potential] by 30 percent since, I believe, 2013,” he said.
Polyplastics Group: Meeting needs for insulating and conductive materials
Controlling heat and reducing environmental impact are two aims of resins supplier Polyplastics Group in its work with the evolving automotive industry.
The shift toward electric and hybrid vehicles is bringing increased demand for components with insulation properties, said Katsutoshi Kasuya, CEO of Polyplastics USA Inc.
“Polyplastics is working on the development of engineering plastics to meet the need of electrification,” Kasuya said. “Specifically, grades of PPS and PBT (polybutylene terephthalate) are expected to play an active role in the future.”
In February, the company launched sales of a new electrically conductive grade of Duranex PBT for millimeter-wave-radar applications. Duranex PBT 201EB provides the benefit of electromagnetic wave shielding — an advantage that means using it requires less assembly work and cuts cost. It bonds extremely well due to its double-shot molding capability.
In addition to introducing engineered plastics to meet the needs of EV manufacturing, Polyplastics is working with automakers and suppliers to reduce the carbon footprint and the amount of virgin materials used in vehicle parts. One example of the new kinds of materials it’s released includes bg-POM, a polyoxymethylene made from methanol produced by biomass raw materials.
“In that sense, from the view of carbon neutrality, Polyplastics is actively promoting the development of grades with low PCF [product carbon footprint], such as bg-POM, in addition to working to reduce the carbon footprint of existing grades,” Kasuya said. “From the view of the circular economy, Polyplastics will also promote engineering plastic recycling, starting with recycling sprues and runners of customers.”
Bruce Geiselman, senior staff reporter
Contact:
Ineos Composites, Dublin, Ohio, 614-790-9299, www.ineos.com/businesses/ineos-enterprises/businesses/ineos-composites
Mubea Inc., Auburn Hills, Mich., 248-393-9600, www.mubea.com
Polyplastics USA Inc., Farmington Hills, Mich., 248-479-8928, www.polyplastics-global.com
SABIC, Houston, 800-845-0600, www.sabic.com/en
Solvay Materials, Alpharetta, Georgia, 770-772-8200, www.solvay.com
Teijin Automotive Technologies, Auburn Hills, Mich., 248-237-7800, www.teijinautomotive.com
