In-Mold Paint
Romeo RIM, Inc was among the first RIM companies to commercialize in-mold paint (IMP) during the 1980's. Their initial application was a heavy truck engine cover with medium gloss requirements.
Romeo RIM continued to innovate and over the last decade has introduced soft touch in-mold paint (ST-IMP) for interior applications requiring a tactile feel, and high gloss in-mold paint (HG-IMP) typically used for rugged structural reaction injection molded parts.
The IMP process involves painting the mold cavity immediately prior to injecting the polyurethane material. During the molding process the coating chemically bonds to the polyurethane thereby eliminates the possibility of the paint chipping and flaking-off , which can occur with post applied paint.
One of the largest costs of painted plastic parts is the painting and finishing process. This includes not only the cost of the paint and labor but also overhead costs of painting equipment, drying ovens, environmental protection equipment and other costs. Although, in-mold paint minimizes these costs, the greatest cost savings are achieved by processing efficiencies that eliminating post-mold painting steps such as cleaning, prepping and priming and improving first run yields.
In-mold painted surfaces perform as well, or better, than post-painted surfaces because the paint chemically bonds and becomes an integral part of the substrate, which is not typical of the mechanical bond realized with post-mold painting.
Consequently, in-mold paint doesn't crack or peel as readily as a post-mold applied paints when a part is scratched, dented or otherwise subjected to real-world wear and tear.
In-mold painted polyurethanes have also performed as well as, or better than, post-painted coating when exposed to relevant durability tests such as dynamic impact, gravelometer, hot/cold aging, abrasion and humidity as well as chemical exposure to ethylene glycol, unleaded gasoline, diesel fuel, hydraulic fluid, motor oil and sodium hydroxide (2%).