Nail Polish and Nail Varnish
Nail polish , also called nail varnish, is a lacquer applied to toenails and or fingernails for appearance, but also as nail protection. Polishing without adding chemical layers is called buffing.
Nail Polish Constituents
Most nail polishes are made of nitrocellulose dissolved in a solvent (e.g. butyl acetate or ethyl acetate) and either left clear or colored with various pigments. Basic components included are: film forming agents, resins and plasticizers, solvents, and coloring agents. Adhesive polymers (e.g. tosylamide-formaldehyde resin) ensure the nitrocellulose adheres to the nail's surface. Plasticizers (e.g. camphor) are chemicals that link between polymer chains, spacing them to make the film sufficiently flexible after drying. Pigments and sparkling particles (e.g. mica) add desired color and reflecting characteristics. Thickening agents (e.g. stearalkonium hectorite) are added to maintain the sparkling particles in suspension while in the bottle. Ultraviolet stabilizers (e.g. benozophenone-1) resist color changes when the dry film is exposed to direct sunlight. Nail polish ingredients often include toluene. Solvents such as toluene and xylene are petroleum-based products that have been linked to cancer. Formaldehyde (formalin) may cause allergic reactions and is unsafe for use by asthmatic people. It is a carcinogen.
Nail polish makers are under pressure to reduce or eliminate toxic ingredients, including phthalates, toluene, and formaldehyde. In September 2006, several makers agreed to phase out dibutyl phthalate, which has been linked to testicular problems in lab animals and humans, in updated formulations. Some makers eliminated formaldehyde from their products, others still use it.
A recent development is water-based nail polish, which is based on an acrylic polymer emulsion (e.g. styrene-acrylate copolymer), and pigments similar to those used in watercolor paints. This is marketed as an environmentally-conscious product, since nail polish is considered a hazardous waste by some regulatory bodies (e.g. Los Angeles Department of Public Works). In this application, the solvent (water) does not completely evaporate as in the case of the traditional nail polish; part of the water is absorbed through the fingernail.
Nail Polish Remover
Nail polish is easily removed with nail polish remover, which is an organic solvent, but may also include oils, scents and coloring. Nail polish remover packages may include individual felt pads soaked in remover, a bottle of liquid remover that can be used with a cotton ball or cotton pad, and even containers filled with foam and remover that can be used by inserting a finger into the container and twisting until the polish comes off.
The base solvent in nail polish remover is usually acetone or ethyl acetate. Acetonitrile has been used, but is more toxic and is banned in cosmetics (including nail polish removers) in the European Economic Area since 17 March 2000.
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