Shimmering layers
The basic technology — which Merck has mastered to the point of market leadership — relies on the layer-substrate principle. Extremely thin layers of metal oxides are deposited on thin plates of a substrate, such as the mineral mica. This is how to achieve the classic pearl effect — almost a synonym for Iriodin, which has meanwhile become one of Merck’s traditional brands. “The effect functions in exactly the same way in natural pearls,” explains Pfaff, “The oysters encapsulate mineral materials in a sequence of protein layers, and the resulting alternation of layers with high and low refractive indices causes the pearl to shimmer and shine.”Micrometer-size gloss on a very large scale
The basic technology — which Merck has mastered to the point of market leadership — relies on the layer-substrate principle. Extremely thin layers of metal oxides are deposited on thin plates of a substrate, such as the mineral mica. This is how to achieve the classic pearl effect — almost a synonym for Iriodin, which has meanwhile become one of Merck’s traditional brands. “The effect functions in exactly the same way in natural pearls,” explains Pfaff, “The oysters encapsulate mineral materials in a sequence of protein layers, and the resulting alternation of layers with high and low refractive indices causes the pearl to shimmer and shine.”
Micrometer-size gloss on a very large scale
The latest generation of Merck pigments based on glass plates has reached the smallest particle sizes — down to a diameter of ten micrometers (see box). “Nonetheless, we have to succeed in manufacturing them on an industrial scale,” says Pfaff. This is because the manufacturing tolerances shrink too. Variations of just a few billionths of a meter in the pigment layer thicknesses would change their appearance. “Once we have developed a new pigment — one that we in the lab like the look of — we work with our colleagues in the technical center to develop a process on a scale of up to 500 liters. Soon, we have a few kilograms, which we test. When we are satisfied, we can move on to larger quantities.” Pfaff, who has been researching at Merck for 18 years, is sure of one thing: “There will be more surprising innovations. Again and again during my years of work here, I’ve been deeply impressed by the ideas we have been able to implement. And we’ve got new ones in the pipeline. But I’m not going to tell you what they are — not yet.”
| Beauty alone isn’t enough |
| Continuous innovation has given Iriodin, the renowned pearl-effect pigment from Merck, an entire family of younger “siblings,” which not only offer beauty, but also considerably more utility. Minatec® pigments, for example, are electrically conductive and can thus conduct unwanted static charge away from a surface. Solarflair® is designed to stop dark red light, so it can keep heat out of greenhouses that have been coated with it. Lazerflair® makes it possible to mark plastics using a laser beam. And the latest additions to the family are the Miraval® pigments. Lake many more recent developments, they are no longer based on natural mica. Instead, they use a synthetically produced borosilicate substrate, which gives them an especially intense rainbow effect and great brilliance. They are also extremely fine, which enables product designers to achieve a very elegant gloss design. The latest pigments in the Miraval® Magic range have particle sizes of as little as 20 micrometers, and those in the Miraval® Scenic range are even smaller, at ten micrometers. Their coatings have thicknesses ranging from 50 to several hundred nanometers. |
