Cosmetic compositions containing crosslinkable polymers

The invention is in the field of cosmetic compositions, in particular, crosslinkable, semi-permanent compositions for application to keratinous substrates such as nails, hair, or skin which contain crosslinkable film forming polymers; crosslinked, semi-permanent compositions on keratinous substrates such as nails, hair, or skin, which contain crosslinked film forming polymers; and processes for providing such semi-permanent, crosslinked compositions to the surface of keratinous substrates such as nails, hair, or skin, whereby crosslinking of the film forming polymer is effected after coating of the keratinous substrate. A cosmetic composition which provides a semi-permanent, crosslinked film on a keratinous substrate, comprising a film-forming polymer having functional groups capable of cross-linking upon exposure to a cross-linking agent reactive with the functional groups; a cross-linking agent reactive with the functional groups of the film-forming polymer; a dissipatable blocking agent which is operable prior to dissipation, to block the cross-linking agent from cross-linking the functional groups of the film-forming polymer, and which, after dissipation, leaves the cross-linking agent free to cross-link the functional groups of the film-forming polymer.