New Pigments Shift Hues in Clear Plastics.

Highly reflective, inorganic interference pigments that provide high chromaticity and shifting hues in clear plastics are newly available from Flex Products, Inc., Santa Rosa, Calif. ChromaFlair pigments are flat, smooth flakes of aluminum, magnesium fluoride, and chromium about one-fiftieth the diameter of a human hair. The reflective aluminum core provides the light interference responsible for color shift. The core also lends hiding power. They are wetted with propylene glycol n-propyl ether to reduce dusting. The flakes create colors that change when viewed at different angles. Eight standard colors include gold/silver, red/gold, magenta/gold, purple/orange, blue/red, cyan/purple, green/purple, and silver/green.

These pigments are best suited to clear, glossy plastics, such as PET, ABS, SAN, and polycarbonate. If used with HDPE and other translucent resins, a more muted color effect will result. These pigments have been tested in injection and blow molding, film extrusion, and calendering. They reportedly are more robust than mica or aluminum flakes in masterbatch production.