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From pearl shimmer to rainbow colors and the illusion of depth



The GRAFE-Group from Blankenhain, Germany has collaborated with Schlenk Metallic Pigments GmbH from Roth, Germany to create a unique development project in which light reflections in all the colors of the rainbow shimmer impressively on a plastic surface and create a hologram effect. Subsequently, in collaboration with the responsible for design and production at Koziol GmbH, based in Lauterbach, Germany, this project was successfully implemented for the first time. Koziol is a leading manufacturer of plastic design articles for the home and office. The manufactured product is a beautiful stand with shelves. Advantages of this designer piece are its different surfaces, since they show the effect of the pigment on glossy and matt structures.


It had previously not been possible to incorporate appealing hologram effects in thermoplastics with higher processing temperatures, explains Danny Ludwig, Director of the GRAFE-Design-Center. "Instead, only color changing effects in the range of two or four colors were available: in other words, the change in the color impression at different viewing angles." With the "MultiFlect®", SCHLENK (a manufacturer of metal powders, pigments and films) has managed to develop a holographic effect pigment which has diverse, stunning effects, depending on the application and lighting: from pearl shimmer to rainbow colors and the illusion of depth.
The "MultiFlect®", which is manufactured in a special production process, is normally used in the automotive sector in wheels paints or for decorative printing applications. Thanks to the color specialists at GRAFE, a plastic application has now also been able to be implemented in the form of a stand with shelves. "If customers want a rainbow effect, we can now offer that," explains Dr. Frank Maile, Head of the Coatings & Plastics Business Unit at SCHLENK. Technically, the effect pigment is referred to as "polychromatic", i.e., generating a multi-colored interference effect.


Hologramm-Effekt_Etagere Koziol

"During processing, plastic is exposed to mechanical and thermal stresses, which previously prevented an appropriate pigment from being used. With our expertise in equipment and recipes, we have been able to achieve the incorporation into the desired target polymer at a dosage of two to three percent, thereby achieving a three-dimensional color effect. We had to perform extensive tests in order to define the machine parameters and screw configurations of the extruder as well as to develop the masterbatch formulations accordingly," says Mr. Ludwig.
It should also be mentioned that applications in polyolefins are easier to implement than in technical materials, since these have higher processing temperatures and higher frictional forces (among other reasons). Meanwhile, though, initial recipes for technical polymers (such as polycarbonate) have also entered the test phase. "With the help of our well-equipped technical center, we have been able to work out a special batch which works very effectively on the laboratory side and which is now undergoing further tests at our customer's premises," says the Director of the GRAFE-Design-Center, who also points out the popularity among prospective customers. "The feedback has been overwhelmingly positive."
This has also been confirmed by Dr. Maile of SCHLENK. MultiFlect® is an extremely important eyecatcher due to its optical properties. The angle-dependent polychromatism and the "rainbow effect" guarantee a high level of attention of products pigmented with MultiFlect®. In spite of the premium price segment, customers are willing to invest in higher raw material costs. However, holographic pigments of this type have also already been used as a distinctive safety feature in applications such as banknotes. Along with LEDs, the pigment can also be used in interior design, since the light sources would additionally emphasize the effects. In March of this year, SCHLENK received the "Innovation Material Award" from the New York consulting company "Material Connexion", the database of which is used by designers and product developers worldwide as an idea exchange.

GRAFE at exhibition K2016 in Düsseldorf: hall 6, booth E75


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