SRG Global develops new polymer for chrome-plating exhaust systems

Novi, Mich. — Not long ago, the automotive exhaust pipe was strictly a functional component with no decorative nature, said Mark Peter, materials innovation engineer at SRG Global Inc.

The pipe was merely an extension of the exhaust system used to emit gas that was created by the combustion engine, he said at the Plastics and Rubber in Automotive conference, Jan. 15 in Novi.

Auto supplier SRG Global has developed ThermoPlate, a material that can be used to replace metal for high-heat, high-strength applications.

"As the industry is evolving, SRG Global is continuously looking for ways to innovate and integrate new technologies into the decorative features that we have in the vehicle," Peter said. "As we're looking to invest in new technologies — the research and development of new technologies — we make sure they fall within one of our four megatrends."

Those four megatrends are move to zero, connected world, urbanization and individualization. Peter said this technology incorporates "move to zero," meaning fuel efficiency and reducing weight of the vehicle, and "individualization," as in adding decorative features.

Exhaust tips of the past might reach around 750° F, "close to that temperature of exhaust," Peter said. Decorative bezels are now around 320° F in day-to-day driving conditions.

"Our innovation team asked ourselves, 'Now that it's 160° C [320° F], why can't we make that out of plastic like every other trim component on the vehicle today?" Well, here's why: Nobody can do it today because the two most common materials in the plating industry are ABS and [polycarbonate]/ABS," Peter said.

He said ABS starts failing around 180° F and PC/ABS around 194° F.

"The fascia-mounted tailpipe bezel, although significantly lower than the previous versions of the welded exhaust tips, still reach 160° C [320° F]," he said. "Obviously, we couldn't use these material selections in this application. As a result, SRG Global partnered with a strategic supplier of ours, Lotte Advanced Materials."

And thus, ThermoPlate was born.

Peter said SRG and Lotte believe ThermoPlate is the first of its kind that is not only decorative but also can survive temperatures up to 390° F — even up to 500° F in short durations.

To do so, they had to understand how to make a resin high temperature.

The known methods to increase the temperature resistance of a polymer included substitution of aliphatic units with aromatic units, addition of stabilizer or reinforcing materials such as glass fibers and mineral fillers, and increasing the degree of polymerization.

One of the advantages of ThermoPlate is weight savings, which increases fuel efficiency.

"We save about 40-60 percent weight," Peter said. "We also offer cost savings relative to stainless steel, about 5-10 percent."

Another benefit is design flexibility.

"Studio is constantly going to the engineering team, saying, 'I want to design this.' But with angles and drafts and everything like that, sometimes it's hard for engineering to do it, but we can design a lot more geometries in an injection mold than you can stamp out of metal," Peter said.

Other advantages include reduced number of parts and complexity as well as aesthetic harmonization of the tailpipe cover and the rest of the vehicle.

"Every single chrome-plated part of the vehicle is chrome-plated ABS or PC/ABS, and you have this one decorative component made of stainless steel that doesn't match," Peter said. "But because we can use some of the exact same process to do with ABS, now not only do we have a perfect match with surrounding trim, but we can offer all the other technologies we have today — the dark chromes, the satin chromes, the bright chromes, the colored chromes — and now we have an infinite range of things we can offer to our customers as they're seeing the industry, [and] the customers [are] wanting to personalize their vehicles more."

Peter said ThermoPlate is considered "fully validated technology." Outside of the automotive industry, it is being considered in other applications.

?​ Aesthetic harmony: ThermoPlate uses the same material and processes as other components near it, which means it will be a perfect match and offer more options for customers.

?​ Design flexibility: The injection molding process offers more options in terms of "designing a lot more geometries," compared with stamping metal, Peter said.

?​ Weight savings: Peter said ThermoPlate saves about 40-60 percent in weight. It also offers between 5-10 percent cost savings relative to stainless steel.

Mark Peter, materials innovation engineer at SRG Global Inc., outlined ThermoPlate's benefits at the Plastics and Rubber in Automotive conference on Jan. 15 in Novi, Mich.

ThermoPlate benefits

SRG Global's thermoplate product

The automotive supplier has developed ThermoPlate, a material that can be used to replace metal.