The term "acrylic nail polish" can apply to two types of fingernail polish. One is produced specifically for use on acrylic or false nails. The other is a water-based acrylic paint.
The Chinese are credited with the invention of nail polish around 3000 BCE. These original formulas were a combination of beeswax, gelatin, gum arabic, and egg whites with flower petals mixed in to create a red color. The Egyptians weren't far behind, using a henna mixture for a red- or orange-hued polish about the same time. By 600 BC, the Chinese were using silver and gold to symbolize royalty, while only the aristocracy were allowed to wear polish at all. Egyptians of that time were also using color to symbolize royalty with red the color of choice for both Cleopatra and Nefertiti.
Polishes of the 20th century were largely enamel-based paints, as are the present day polishes made for acrylic or false nails. They are made by putting a drying enamel acid together with alcohol. Tiny fibers, or resin, float in the enamel mixture. A special solvent evaporates and cures the resin through oxidation. Left behind is a tough yet flexible fiber-based color.
In 2003, nail polish makers developed a water-based formula that is based on an acrylic polymer emulsion. Much like enamels, the acrylic nail polish has tiny particles of acrylic resin. The difference is that they are suspended in water rather than alcohol. The water part of the polish is partially evaporated and partially absorbed into the fingernail. The resin left behind fuses together and creates a strong polish.
There are a few practical advantages to using water-based polish. The smell is significantly less offensive than alcohol-based products, and the drying time is usually shorter. Cleanup of acrylic paints is generally easier since they will peel off of most surfaces.
Environmentalist concerns have sparked some research into the claims that water-based acrylic nail polish is safer than enamels. Enamel nail polish is categorized as a hazardous material. Water-based products have been touted as a safer type of paint that is non-combustible and can be considered more environmentally friendly. The ingredient list of many acrylic polishes is vague, however, listing "acrylic polymer emulsion" as one of the main ingredients. Since these emulsions are not always chemical-free, there is some debate about just how environmentally friendly they are.