The Chemistry of Nail Polish

Composition of ...

• methacrylate
• vinyl polymers
• formaldehyde
• camphor
• acetone
• ketone
• toluene
• suspending agents
• film forming agents
• resins and plasticizers
• solvents
• and coloring agents

Chemistry's Role

The pigments are mixed with nitrocellulose and plasticizer using a "two-roll" differential speed mill. This mill grinds the pigment between a pair of rollers that are able to work with a speed that increases as the pigment is ground down. The goal is to get fine dispersion of the color.

• When properly ground down, the mixture is removed from the mill in sheet form and then broken up into small chips for mixing with the solvent. The mixing is performed in
• stainless steel kettles that can hold anywhere from 5 to 2,000 gallons. Stainless steel must be used because the nitrocellulose is extremely reactive when near iron. The kettles are jacketed so that the mixture can be cooled by circulating cold water or another liquid around the outside of the kettle. The temperature of the kettle, and the rate of cooling, are controlled by both computers and technicians.
• This step is performed in a special room designed to control the hazards of fire and explosion.
• Materials are mixed in a closed kettles. At the end of the process, the mix is cooled slightly before the addition of such other materials as perfumes and moisturizers.
• The mixture is then pumped into smaller, 55 gallon drums, and then trucked to a production line. The finished nail polish is pumped into explosion proof pumps, and then into smaller bottles suitable for the retail market.

A solvent is the liquid in which the resins and pigments are dissolved or suspended. Nail polish, or any other paint, flows because of the solvent. Since once it's put on your nails you don't want it to flow any more, you want the solvent to go away as quickly as possible.

• This can be done in two ways.
• Use a solvent with a low boiling point so that it will evaporate quickly. This is the simplest way of doing it and is most commonly used. all house paints and even industrial exterior paints dry by evaporation of the solvent.
• Use a solvent which will solidify (usually by polymerizing) on exposure to some outside agent (oxygen, UV light, electricity, another liquid with which it is mixed just before applying, ...) This is much trickier - you don't want your nail polish to harden before you apply it! - and tends to be used either in,super glue and epoxy cement, for example; the one dries on exposure to air.

Background Research

• you can keep nail polish in the fridge
• most are flammable
• most go bad after about 2 years
• it is close to the chemical composition of car paint
• some chemicals in nail polish are known to cause cancer
• Nail polish was invented by the Chinese in about 3000 B.C. It was made from a mixture of Arabic gum, egg whites, gelatin and beeswax. It is unknown who the first person was to invent nail polish, but it was used by the ancient Chinese and ancient Egyptians. Chinese royalty often used gold and silver nail polish
• the most expensive nail polish is made of platinum
• During the Ming Dynasty, polish was made from a combination of beeswax, egg whites, gelatin, vegetable dyes and Arabic gum. The polish we use today can give its thanks to the car industry. Today’s polish is a refined version of car paint.
• invented in 1920s and was launched first by revlon
• Ultraviolet stabilizers are used in nail polish so that it doesn’t change color when exposed to light

Resources

enotes.com Gale Group,2002