Shaping keratin fibres using an amine or a diamine

A method for straightening naturally curly hair fibres comprising:

• (a) providing a crosslinking composition, wherein the crosslinking composition is at a pH of 9-10 and comprises:
• an active agent, wherein the active agent is an amine or diamine and wherein the amine or diamine is selected from the group consisting of:
• 1,7-diaminoheptane, 1,4-diaminobutane, 6-aminohexan-1-ol, 6-amino hexanoic acid, 2-aminoacetic acid, 2-amino-2-oxo-ethanoic acid, 4-aminobutanoic acid, and mixtures thereof;
• a photocatalyst which is a mixture of 8-hydroxyquinoline and 8-quinolinol-1-oxide;
• a cosmetically acceptable carrier;
• wherein the crosslinking composition has not been exposed to electromagnetic radiation having a wavelength of 750 nm or less for 30 min or more;
• (b) applying the crosslinking composition to said hair fibres, subsequently drying said hair fibres and then, mechanically straightening the fibres with a hair straightening iron, and exposing the composition to electromagnetic radiation having a wavelength of from about 300 nm to about 750 nm;
• wherein (b) involves elevating the temperature of the hair straightening iron to a temperature of from about 50° C. to about 180° C.;
• and
• wherein the method does not comprise a rinsing step between step (a) and step (b).