Sparkle pigments, properties

Pigments are added to give a plastic color, but fliey may also affect the physical properties. Extenders are usually cheap materials added to reduce the cost of a plastic resin. Dyes are colorants chemically different than pigments. Mica is a special pigment added to impact sparkle or metallic appearance. Titanium dioxide (Ti02) and carbon black are two important pigments that merit further discussion. 

Optical Properties. Many packages need sparkling clarity to display their contents (see Optical Properties). Other packages have printing over nearly all of the surface area or the product must be protected from uv radiation. White, brown, and black pigmented layers are combined to protect light-sensitive products. 

---