Nail Polish Basics                                              Paul Bryson, Ph.D, Director of R&D, OPI Products Inc. 

Nail Polish (a.k.a. Nail Lacquer, Nail Enamel), consists of 6 main types of ingredients:  Pigments, Resins, Solvents, Plasticizers, Dispersants, and UV Stabilizers.  Obviously, the exact proportions of these are corporate secrets!  But, I can tell you what these ingredients are, and what they do. 

 (1)  Pigments (colors) are the essence of polish;  a variety of D&C (drug & cosmetic approved) colorants are used.  Most colors require several different pigments, mixed in the right proportions, to make the desired shade.  Before they are added to the polish, pigments must be ground down with mills to very fine powders -- you don't want big chunks of color ruining the polish coat!  "Frost" and "shimmer" polishes are created by adding sparkling, reflective particles, such as Mica or certain metals or polymer flakes;  the size of the particles partly determines how the polish sparkles.  Colors are often labeled by "CI ######";  this is the Color Index number, which is an internationally recognized way of identifying colors.  

(2)  Resin is the tough material that holds the polish together.  Resins are a type of "polymer", which means, they are composed of giant molecules that were made by linking smaller molecules into long chains and networks.   If you just wanted a colorless nail protector, you could leave out the Pigments, and the nail polish, once dried, would be a clear, tough coating.  It would look a lot like a clear furniture lacquer.  Nail polish uses two types of resin, film forming and adhesive.  Since neither would make a perfect polish by itself, the two types must be blended for optimum performance.  In OPI polish, Nitrocellulose resin is the primary film-former; it makes the polish strong and gives it a shiny, smooth surface, as well as having moderately good adhesion to the nail;  however, too much can make the polish coat brittle.  Acrylates Copolymer is another film-forming resin sometimes added.  Adhesive polymers, which also add some flexibility, include Tosylamide/Epoxy Resin, Polyvinyl Butyral, Adipic Acid/Neopentyl Glycol/Trimellitic Anhydride Copolymer, and Tosylamide/Formaldehyde Resin or “TSFR”.  (Please note:  TSFR is NOT the same chemical as formaldehyde, which is used only in specialized nail hardener products).  

(3)  Solvent is the part of the polish that evaporates, and is responsible for the strong odor.  The solvent must be compatible with the resin, so that the resin can be spread on the nail.  After the polish has been applied, the solvent must evaporate evenly, so that a smooth, hard coat will be left behind. (It's a lot like the way paint works.)  As with paint, if the solvents evaporate too fast, there’s a risk of bubbling or “skinning”; conversely if the solvents evaporate too slowly, there’s a much greater chance that the polish coat will be smudged or nicked before it’s fully dry.  For all of these reasons, much care is devoted to getting exactly the right solvent combination.  OPI's polish uses mainly Ethyl Acetate, Butyl Acetate, Propyl Acetate, and Isopropyl Alcohol.  (OPI stopped using Toluene in 2007.)  If a polish bottle is left open too long, and too much solvent evaporates,  it should be thinned out with a solvent blend such as OPI Lacquer Thinner (not polish remover, which can contain water or moisturizers that would ruin the polish.)  

(4)  Plasticizers are additives that keep the resin flexible after it is dry.  Think of plasticizers as sort of a molecular "lubricant" in between the resin (polymer) chains, that allows them to move around a bit more without breaking.  This makes the resin tougher and less vulnerable to chipping.  Examples of plasticizers include Trimethyl Pentanyl Diisobutyrate, Triphenyl Phosphate, Acetyl Tributyl Citrate, Camphor, Ethyl Tosylamide, and Trimethylpentanediyl Dibenzoate.  (OPI stopped using Dibutyl Phthalate in 2006).

(5)  Dispersants are additives that help the Pigments mix with the Resin and Solvent.  Some pigments have a tendency to settle out of the solvent/resin mixture;  dispersants partially prevent this.  OPI's polish uses Stearalkonium Hectorite and/or Stearalkonium Bentonite, flow control agents which also act as dispersants.  However, even with the best dispersants, some settling out of the pigments may eventually happen;  if so, simply shake (or better yet, roll) the polish bottle before using.

(6)  UV Stabilizers are additives, similar to sunscreens, which help keep the polish from changing color when it is exposed to too much UV light from the sun.  OPI's polish contains Benzophenone-1.

Copyright 2010 OPI Products Inc.