Materials for auto components adapt to EV, sustainability goals

Automotive plastic material designs will have to adapt as auto components shift to accommodate EV, mobility, autonomy and sustainability goals being driven by the "continuously rising greenhouse gas and carbon footprint" of the industry.

By 2040, "not only semiautonomous but potentially full autonomy will become the standard," Rose Ryntz, president of Ryntz and Associates LLC, said May 26 at Plastics News' Plastics in Automotive virtual edition. "The use of different [human-machine] interfaces to those electrified components will be huge.

"From 2015 to 2021, the market has established trust with consumers who've started to accept some control being taken from the driver in favor of autonomous systems," said Ryntz, who was a longtime engineering leader for interior suppliers.

Global and national regulatory bodies creating policies to promote the adoption of energy-efficient vehicles, she said, will help automakers meet an expected goal of 55 percent electrification of global vehicle production by 2040.

As consumers' concepts of vehicle ownership also change, "crafted interiors" will become the new normal to meet requirements for shared mobility and autonomous vehicles.

More resilient and "smart" materials can account for key requirements to interior development like cleanliness or noise dampening that will also affect the shapes of components, Ryntz said.

Microbial growth on some materials can cause discoloration, odor or polymer degradation, she said.

"There are things that can be done with antimicrobial agents to prevent these types of degradation," Ryntz said, like including additives such as chlorine, ammonium, long-chain alkanes or inorganics like silver, copper and zinc halides.

Plastic interior parts in shared vehicles will also need to be durable to the use of any disinfectant and deodorizing sprays.

"Certain basic chemicals, some alcohols, can not only stress craze polycarbonate, but may have some impact on the overall durability of the plastic part," she said.

HEPA filtration and ultraviolet light can help avoid chemical sprays — "depending on the bacteria, it's not one size fits all," she added — and self-healing ingredients like polyrotaxanes in acrylics can help with wear and tear.

"As the combustion engine goes away, we will hear more noise from air, wind, rain and rocks and other things that hit the underbelly of our vehicle," Ryntz said.

Noise from rocks hitting metal and steel chassis, or enclosed battery packs made of aluminum or plastic plus wheels and wheel arches, can be abated using heavy, layered materials, she said, "that contain heavy minerals like barium or calcium in very high levels, used for example between the engine and the interior cabin called a dash mat."

Heavy materials don't go well in combination with trying to lightweight a vehicle, Ryntz said.

Lightweight honeycomb materials, which dissipate the sound through different layers of lattice structures, could quiet the acoustics in electric vehicles.

"Putting some tortuous path through it … with different material properties that can abate that noise altogether," Ryntz said.

Another interior design challenge as the EV market takes hold, she said, is the control of temperature without a combustion engine to expel heat for the passenger cabin.

"That was a perfect heat source," Ryntz said.

Smaller motors or heating pads might be used to emanate heat or blow cold air, she said, while pigments in plastics could also be used to control temperatures.

"Black plastics typically retain and dissipate a lot of the heat," Ryntz said. "Expect a lot of research being done in that area."

As vehicle electronics go through new iterations of technology more and more quickly, new developments will need to go "well beyond the glass or plastic that's used in the curved display," she said.

"Typically, [there is, in] a two- to four-year period, 28-30 new iterative advances in electronics," Ryntz said. "Printing circuits directly on the back of plastic materials holds a whole new array of requirements from that interface between the electronic components and plastics or glass material."

When it comes to sustainable materials and manufacturing processes, "everybody wants it but they don't want to pay for it," she said. "Sustainability is a broader view than just materials. How you manufacture with lower energy sources, additive manufacturing really fits into that."

Companies that have used capacity for slush tooling or thermoforming equipment "may be more apt now to look at additive manufacturing capabilities to increase their capability in the production of different components," Ryntz said.

Instead of having "huge injection molding presses that are taking up a lot of heat and floor space," and the wastewater associated with them, she said, companies can use additive and 3D printing capabilities to reduce the overall cost of tooling or eliminate the need for tools.

"Parts that are additively manufactured don't need tools. It's controlled by software," Ryntz said. "If we can now print parts on demand, we no longer have to worry about inventorying tooling. That's going to take a lot of cost out of that overall development cycle.

"Additive manufacturing has been around for more than thirty years," she added. "A lot of those techniques have grown over the last few years to not just be things for prototype but parts that can be used in production."

Renewable materials "might not be as costly" as OEMs and suppliers expect as more research is done on renewable and nonpetroleum-based fillers, she said.

As volume picks up with material additives like sugar cane, polyolefins and wood-based polyesters, Ryntz said, "we'll see those used to replace some of the plastics we use today," while still allowing products to be Class A, textured and withstand other specifications.

"A revolution is really needed in the automotive interior supply space," Ryntz said.

With more supply chain integration, suppliers will need to work together and more closely to bring crafted interior parts to the market, she said.