A synthetic polymer primarily made from acrylic acid that most commonly comes in the form of a white fluffy powders, and is used as a thickening agent in cosmetic formulas. This is used frequently as gels in cosmetics and in many other cosmetics and personal care product types.
Carbomers normally require neutralising to maximise their viscosity in dispersion. Neutralising effectively raises the pH of the dispersion to that where maximum viscosity is achieved. Un-neutralised carbomer dispersions have a typical pH of 2.5 - 3.5 and have low viscosities. Adding a neutraliser raises the pH and enhances the viscosity. Optimum viscosity is achieved at pH 6.5 - 7.5.
The usual neutraliser in most Carbomer is a solution of 25% sodium hydroxide in 75% water, although some carbomer can also be neutralised with AMP (Aminomethylproprianol) or TEA (triethanolamine). Add enough of the neutralising solution to raise the pH to the optimum level. In most formulas this can be between 1% and 3% depending on the amount of carbomer in the dispersion.