Lexus ES in-mold coating: how the new trunk panel is made and why it matters

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The new Lexus ES has received a technology that isn’t exactly headline material, but matters a lot for a premium car: a large exterior trunk panel with in-mold coating (IMC). It was developed by Kansai Paint and Toyoda Gosei, and for Japan’s auto industry this is the first mass-production use of the technology on a large plastic exterior part.

The idea behind IMC is that molding the part and applying the coating happen inside the mold itself. That removes the need for a separate paint booth and drying oven, cutting production CO2 emissions by roughly 60%. For Lexus, that’s not just an environmental figure: the technology also produces a smoother surface and helps the seam with the glass look cleaner, without a rough transition between the panel and the window.

There’s a practical upside too. Thanks to the urethane coating, the panel should hold up better against damage, and minor scuffs after a wash should be less noticeable. For a premium sedan like the ES, that matters more than it sounds: buyers expect not just a quiet cabin and a soft ride, but also a finish that won’t start looking cheap after ordinary city driving.

Next to the BMW 5-Series, Mercedes-Benz E-Class and Audi A6, this story isn’t about power or infotainment — it’s about manufacturing culture. Lexus has always sold calm, longevity and build precision, and this technology fits that image well. Kansai Paint and Toyoda Gosei are already planning to roll out IMC at other plants, so the ES’s trunk panel could turn out to be the start of a new finishing technology for large Toyota and Lexus parts, not a one-off experiment. This isn’t the new ES’s only piece of clever engineering, either — the car was already spotted with hidden touch-sensitive switches that only appear when a hand gets close.

Sometimes premium quality doesn’t start with a big screen — it starts with a panel the owner only notices after dozens of car washes.