GERHARD PFAFF*, MIRIAM BECKER
*Corresponding author
Merck KGaA Frankfurter Str. 250 Darmstadt, 64293, Germany

Abstract

The history of special effect pigments dates back to the 17^th century. A real breakthrough was achieved with the development of pigments using layer-substrate structures 50 years ago. Platelet-like particles of natural and synthetic mica, silica, borosilicate, and alumina are used today as templates for thin high-refractive metal oxide layers forming attractive pigments with special effects like pearl luster, angle-dependent interference color, sparkle, or multiple reflections. The specific properties of transparent and semi-transparent effect pigments make them unique in a wide range of cosmetic applications – from color cosmetics to personal care products.

INTRODUCTION
What makes modern cosmetics so attractive? It is not only the scientific claim that may be included, often the optical appearance and skin feel triggers the consumer’s decision. Appearance and skin feel of cosmetic products can be enhanced by the use of pearlescent pigments and their broad range of stunning effects. Effect pigments differ from conventional pigments in their special coloristic properties. They are used alone or together with other colorants and also fillers in a wide range of applications such as cosmetic formulations, industrial and automotive coatings, plastics and printing inks.
The cosmetic industry is constantly looking for new coloristic effects, which optically attract consumers. Besides colour and effect, the pigments should also provide advantageous skin caring properties as well as ease of application.
Effect pigments can be divided into the two basic classes: special effect pigments, the most important examples of which are pearlescent pigments, and metal effect pigments. All effect pigments are characterized by a platelet-shaped geometry of their particles. These have a diameter, which lies gener ...