The machine that is cleaning the plant floor resembles a small, futuristic Zamboni, and it is scrubbing and vacuuming at the same time. Watching this unit diligently comb the pristine expanses of Soliant’s 100,000-ft2 (9290-m2) factory in Lancaster, SC, is the first hint that the process of manufacturing paint film requires exceptional cleanliness.
“This is a Class-10,000 clean room,” said Jeff Bailey, Vice President of Operations, as he escorts us into the plant’s main coating department. Here, the coating lines are running at a rate of 100 ft (30.5 m) per minute, producing “more square footage of paint film than anyone else produces in the world,” he claimed.
While traditional paint still dominates automotive-exterior coatings, paint film is steadily replacing it on those surfaces that must deliver high wear resistance. Made by Soliant and competitors including Avery-Denison, Decoma, and Mayco-Schulman, paint film is an ultra-thin painted elastic film that is bonded to plastic parts (in a variety of substrate types) during their molding.
Once applied to the part, the films are invisible to the eye. They are used to protect a growing list of Class-A parts—bumper fascias, door sills and rocker panels, body side moldings, roof pillars, and even heavy-truck radiator grilles—from damage due to stone chips or even overly abrasive car-wash brushes. A variant, known as bright film, is proving to be a convincing substitute for chrome-plated, polished, or brushed metal.
“In the world of automotive coatings, films are a disruptive technology,” said Bailey. “The paint industry is our biggest competitor.”
Achieving consistent quality and color (the company offers more than 1400 colors) in its Flourex line of films requires rigorous process control, noted President Jerry Patton. Soliant’s product begins with a clear sheet of base film purchased from a supplier. This material is 0.001 to 0.006 in (0.0254 to 0.1524 mm) thick, depending on application, and serves as a carrier for the color coat.
Resembling a jumbo roll of kitchen wrap 48 or 60 in (1220 or 1524 mm) wide and 15,000 ft (4572 m) long, the base film is continuously fed through a printing-press-like coating machine. The multistage mechanism first applies a clear coat, then a pigmented color layer of paint, then the adhesive layer that will laminate the film to the part when it is molded.
The base film is then stripped away, leaving a flexible, durable, high-gloss coating. The finished product is shipped to Soliant’s Tier 1 customers, who typically use thermoforming (also known as vacuum forming) to apply paint films on high-volume plastic parts.
When film technology first entered the industry, it did so mainly with injection molding. But the trend has moved to thermoforming because tooling costs are up to 50% less and finished-part quality higher, said Bailey. Extrusion and compression- and blow-molding also are used.
Durakon is thermoforming 250,000 rocker panels per year for General Motors’ Buick Lucerne using Soliant Fluorex paint film in a 14-color pallete including metallics and pearlescents, noted Durakon President and CEO Ed Gniewek.
The parts are finished right out of the mold, he noted. Concept-to-production time is also significantly less than when using injection molding—Durakon typically executes a thermoformed paint-film component program in 10-12 weeks, about half the time, on average, required by competitive injection molders, according to Gniewek.
Part-to-part cycle times with thermoforming are less than 1 min, including robotic trimming and packing, he said.
By coloring the thermoformed part using paint film rather than paint, the parts-processor eliminates both a paint shop and the volatile organic compounds (VOCs) that accompany it.
However, most of the paints used to make film are solvent-borne (though some layers are water-borne). Soliant’s plant complies with U.S. EPA Title-5 regulations, which means it must capture 100% of VOCs emitted during film production. It then eliminates more than 98% of them by incineration.
“We’re adding additional VOC-abatement technology—higher capacity equipment,” noted Patton. He said this will not only help lower the plant’s emissions but also reduce its consumption of natural gas used to fuel the incineration system.
Soliant’s paint-film manufacturing process won the Environmental Award in the “Emerging Technologies” category at the 2006 Society of Plastics Engineers—Global Plastics Environmental Conference.