Wacker silicones give waste material new life

DUESSELDORF, Germany—Wacker Silicones, a major business segment of Wacker Chemie A.G., is focusing on innovations in sustainability and e-mobility at K 2022.

The Munich-based silicone giant, in its standard spot at the expansive show, hosted a gathering for the press Oct. 19 in a self-proclaimed "speed dating" forum, allowing journalists to briefly interview Wacker experts on a range of topics.

Klaus Pohmer, global segment manager for performance silicones, said its pioneering biomethanol-based silicones meet the same performance characteristics as fossil fuel-derived legacy feedstocks, and use far less CO2 in their production—and, therefore, have less of an impact on the environment.

"When we are thinking about raw materials, we begin with inorganic quartz (refined silicon, ultimately), and then other groups are introduced, including fossil fuel methanol," Pohmer said. "It makes sense to use fossil-free materials, and we have found that our silicones are continuously moving into other applications."

It is a project that Wacker began about three years ago, and it remains a challenge in progress, Pohmer said.

Rather than using vegetable oils or methanol derived from another agricultural commodity that is a necessity for human consumption, Wacker has pioneered a methanol process using trash- and waste-derived material.

Wacker began looking at green methanol in 2019.

"We use the same production lines … they are exactly the same," he said. "We need no additional testing, and they can be used in all the same applications."

The development of this "one step" demonstrates that Wacker is committed to a sustainable future, Pohmer added.

"We have serious carbon-neutral targets in this race to zero," he said. "2045 is one thing, but we want to reach 50-percent carbon neutral by 2030.

"This is a start. It has its advantages, and it shows our commitment to the future."

Pohmer added that the amount of CO2 that could be saved with this method is not yet quantifiable, though Wacker officials expect it to be significant.

He cautioned that the green methanol feedstock is just "one step" in the path toward sustainability, as Wacker "races to zero" in its net GHG production by 2045.

In the production of silicone, the largest producer of CO2 (by a wide margin) remains silicon metal refinement—where massive amounts of energy are required to refine the metal from quartz (SiO2).

Typically, coal or natural gas provides this energy, and this can lead to brownouts, as has occurred in China, negatively affecting both the climate and global supply chain.

"It is challenging to talk about the future; it is easy to look backwards," said Christian Gimber, vice president of the silicone engineering business unit. "The most important is the 'how' for Wacker."

Wacker was present at the first K show 70 years ago, and is celebrating 75 years of its silicone business this year.

"We really have something up our sleeve here with green silicones," said Florian Degenhart, corporate communications and media relations director for Wacker Chemie.

"I submit here that this is one thing," Pohmer told Rubber News. "It is one step of many. I always compare this to green power … with black methanol and green methanol, we need to consider the mass balance between them."

Pohmer reiterated that inorganic and organic methanols offer no change in the overall silicone performance.

Electric vehicles are expected to contain about four times more silicone than legacy internal combustion engine vehicles.

On average, there is between 1.5 and 3 kilograms of silicone in a normal internal combustion engine (ICE) vehicle; that is expected to increase to between 10 and 12 kilograms in EVs, according to Wacker experts.

"This is a great challenge and a great playground for us," said Sebastian Rommel, segment manager for automotive.

One of the key issues Wacker faces moving forward is thermal management.

"To us, this means opportunity," Gimber said Oct. 19. "I expect that more traditional applications will drop off, and we are actively engaged in new product applications that will overcompensate our sales into this market."

This has accelerated in the past few years, Gimber said, as fuel cell and battery management are concerned.

"If you remember, you could not turn on your Galaxy phone in an airplane due to the heat dissipation, or failure thereof," he said. "We want to make sure this does not happen in cars as you are sitting in them … and to do this you need some very clever materials."

A "thermal event," said Michael Kalchauer, technical manager for industrial solutions, could see temperatures reach anywhere between 1,000° and 2,000° C.

Gimber said Wacker also is looking beyond elastomers to reach this thermal management goal.

"Very rarely, but sometimes we do," he said. "Thermoset material is very different from our product range and we are examining silicone resin that allows for heat-stable parts."

Rommel and Kalchauer, said the EV/silicone revolution is something new for both Wacker and OEMs.

"Gap fillers between the fuel cells require more than one challenge," Kalchauer said. "And this is a new learning phase for OEMs as well. So, we need to adjust our products to fit with the OEM's project."

Within an EV, silicone is used in the heads-up display for optical bonding; in sensors for the encapsulation of electronics; in the fuel cell itself for the sealing of bipolar plates; for electrical insulation in high-voltage cables; in high-voltage connectors; in the battery system itself for thermal management; in the e-motor for coil impregnation and active cooling; and in the power conversion system for encapsulation of electronic and thermal management.

"To ensure long-life stability in harsh conditions—like changing temperatures, charging and fast driving—we need continuous improvement," Kalchauer said. "Every project is a living project."