Two-stage process for dyeing keratin fibres

Process for dyeing keratin fibres which comprises:

• (a) treating the fibres with a first composition which has a pH from 7 to 13 and contains an oxidative dyestuff precursor of the para type selected from the group consisting of:
• a para-aminophenol;
• N,N'-diarylalkylenediamine in which the aryl groups are substituted in the para position by OH or an amino group wherein the amino group is unsubstituted or substituted by an alkyl group, wherein the aryl groups are independently unsubstituted, alkyl-substituted or halogen-substituted, and in which the alkylene group contains a chain hetero-atom of oxygen or nitrogen, and is unsubstituted or hydroxy-substituted or alkyl-substituted, the nitrogen atoms of the alkylenediamine group being unsubstituted, alkyl-substituted, hydroxyalkyl-substituted or aminoalkyl-substituted;
• and
• a compound of the formula:
• ##STR12## in which:
• R.sub.1 and R.sub.2 independently of one another denote hydrogen, phenyl, furfuryl, tetrahydrofurfuryl or a linear or branched alkyl group which is unsubstituted or chain-terminated by a hydroxyl, alkoxy, a primary, secondary or tertiary amino group, acylamino, alkyl or aryl-sulphonyl-amino, carbalkoxyamino, ureido, carboxyl or carbamyl in which the nitrogen atom is unsubstituted or mono- or di-substituted, said alkyl groups including alkyl groups containing oxygen or nitrogen atoms and alkyl groups substituted by hydroxy or amino groups;
• or R.sub.1 and R.sub.2 together form, together with the nitrogen atom to which they are attached, a heterocyclic ring;
• and R.sub.3, R.sub.4, R.sub.5 and R.sub.6 independently of one another denote hydrogen, halogen, linear or branched alkyl which is unsubstituted or substituted by one or more OH, amino or alkoxy groups, or a group OZ, Z denoting alkyl, hydroxyalkyl, alkoxyalkyl, acylaminoalkyl, carbalkoxyaminoalkyl, mesylaminoalkyl, ureidoalkyl, aminoalkyl or mono- or di-alkylaminoalkyl, the alkyl radicals containing 1 to 6 carbon atoms, with the proviso that if R.sub.2 denotes phenyl, R.sub.1, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 denote hydrogen, and that if R.sub.1 and R.sub.2 are both different from hydrogen, R.sub.3 and R.sub.6 both denote hydrogen or an organic or inorganic acid salt thereof;
• and mixture thereof;
• and
• (b) subsequently, without any intermediate rinsing, treating the said fibres with a second composition which has an acid pH and contains a coupler of the formula:
• ##STR13## in which:
• X denotes --OH, --NH.sub.2 or --N(CH.sub.3).sub.2, R.sub.21 or R.sub.19 denotes H or an alkyl radical having 1 to 4 carbon atoms, R.sub.20 denotes COCH.sub.3, CONH.sub.2 or an alkyl radical having 1 to 4 carbon atoms, R.sub.22 denotes hydrogen, --COCH.sub.3 or --CONH.sub.2, and R.sub.23 denotes OH or amino, or an organic or inorganic acid salt thereof, or 6-aminoindoline.