Introduction

The invention is related to photostable dyes for semi-permanent or direct hair dyeing. The dye is encapsulated in substantive cationic microspheres. The invention also relates to the process used to obtain the cationic microspheres containing colour.

Technical features

The invention relates to micro-encapsulated dyes using substantive microspheres, having the ability to bind to keratin. The micro-encapsulated colorants obtained are stable, retain their chemical-physical, organoleptic and functional properties. In detail, the encapsulation of the dyes in the substantive cationic microspheres allows to obtain stable dyes (UV or visible irradiation), long-lasting (resistant on the  hair), uniform and without adverse effects, for example concerning the biocompatibility and safety of the skin. The invention also relates to the process for the formation of cationic microspheres containing colour, obtained by the method of emulsion, evaporation of the solvent in which a methacrylic polymer and the colour are dispersed in a volatile solvent and then the obtained dispersed phase is emulsified with a dispersing phase. After evaporation of the solvent, the microspheres are harvested by filtration, washed and finally dried.

Possible Applications

• Cosmetic sector:
  • Hair beauty products;
  • Nail dye products;
  • Skin care or skin decoration products;
• Biocompatible and safe colours for the skin.

Advantages

• High physico-chemical affinity for keratin;
• Photostable, long-lasting, resistant to hair and uniform dyes;
• Dyes without any adverse effects, such as biocompatibility and skin safety;
• High quality of result and variety of tones obtainable.