How DYES Behave - A Bit About PPD

Aside from Henna, most every hair dye is a synthetic dye. Synthetic dyes are produced

from various chemicals. Chemical dyes are available at an affordable cost, have fine

optical properties (color) and resist fading. Both Dyes and Pigments are colored

because they absorb only some wavelengths of visible light. Dyes are usually soluble in some solvent. Pigments are NOT soluble.

Certain dyes can be made insoluble with the addition of salt to produce what is called a

"lake pigment".

In hair dyes: (PPD) p-Phenylenediamine is the chemical compound commonly found as

an ingredient in hair dye. It is an organic compound. with the chemical formula:

C6H4(NH2)2. It is a derivative of ANILINE which is a white solid. This is mainly used as a component in most hair dyes. Some manufacturers utilize PTD, rather than PPD when

manufacturing their hair color brand.

Newer chemical additions which may replace PPD in hair dyes by other other analine analogues and derivatives like 2,5-diamino(hydroxyethylbenzene) and 2,5-diaminotoluene. Other popular precursors includeindophenols. Derivatives of diaminopyrazole help create both red and violet shades. In these applications, the nearly coorless dye precursor oxidizes to the dye.

NOTE: PPD is also used as a henna substitude for tempprary tattos. Its usage can lead to

severe contact dermatitis. In 2006, PPD was noted as being the tenth most prevalent allergen in patch tests. (5.0 Percent). It is listed as a contact allergen which can cause

reactions within a small group of individuals.