Phthalimides as bleach activators

An agent for lightening keratinic fibers comprising, in a cosmetic carrier:

• (i) at least one oxidizing agent chosen from hydrogen peroxide and/or one of the solid addition products thereof onto organic or inorganic compounds, and
• (ii) at least one cationic phthalimide according to formula (I),
• wherein
• R1 and R2 are each mutually independently a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a partially or completely halogenated C1-C6 alkyl group, a C2-C6 alkenyl group, a C1-C6 hydroxyalkyl group, a C2-C6 polyhydroxyalkyl group, a hydroxyl group, a C1-C6 alkoxy group, a nitrile group, a nitroso group, a nitro group, a carboxylic acid group, a sulfonic acid group, a sulfonamido group, an amino group, a di-C1-C6-alkylamino group, a mono-C1-C6-alkylamino group, a C1-C6 alkoxycarbonyl group, an optionally substituted aryl group, or an optionally substituted heteroaryl group, or
• R1 and R2 form, together with the adjacent benzene ring, a further phthalimide unit according to formula (Ia),
• R3, R4, R5 are each mutually independently a C1-C6 alkyl group, a partially or completely halogenated C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 hydroxyalkyl group, a C2-C6 polyhydroxyalkyl group, a C1-C6-alkoxy-C2-C6-alkyl group, a cyano-C1-C6-alkyl group, an aryl-C1-C6-alkyl group, a carboxy-C1-C6-alkyl group or a sulfonyl-C1-C6-alkyl group, or two of the substituents R3, R4 and R5 form, together with the attached nitrogen, a 5-, 6- or 7-membered, saturated or unsaturated ring which optionally contains further heteroatoms,
• n is an integer from 1 to 6, and
• A− is a physiologically acceptable anion.