Compositions including polycarbodiimide and derivatives thereof together with carboxylic acid compounds and derivatives thereof chosen from fatty acids, their salts, and mixtures thereof to enhance the quality of the keratinous substrates. The present invention relates to a cosmetic treatment and process for treating keratinous materials, in particular for hair-care and hair-styling, wherein the composition can include the polycarbodiimide and the carboxylic acid compound chosen from fatty acids, their salts, and mixtures thereof in amounts sufficient to impart hydrophobicity to keratinous substrates, including hair fibers, upon application thereto. The present invention, in particular, relates to a hair treatment composition and process for enhancing durable non-permanent shaping and curling of the hair.

A shelf-stable cosmetic agent for temporarily shaping keratin fibers, and in particular human hair, having improved protection against the fading of the color of keratin fibers is provided.

A method of reducing and/or preventing the bleaching and/or fading of artificially produced hair colors, includes the following steps: i. applying a cosmetic composition to the preferably wet, colored hair, ii. allowing the composition to act for a period of at least 5 s, iii. optionally: rinsing the composition out with water. The cosmetic composition, based on the weight thereof, includes a) 0.05 to 0.5 mol/kg of at least one divalent salt of a monobasic organic acid or b) 0.01 to 0.5 mol/kg of at least one monobasic organic acid (b1) and 0.05 to 0.5 mol/kg of at least one divalent inorganic salt (b2), and the cosmetic composition has a pH in the range from 4.0 to 4.8.

Hair treatment agents, containing at least one anionic surfactant, at least one silicone, at least one cationic polysaccharide polymer, o-cymen-5-ol, and at least one organic acid, reduce or prevent the washing out of color from dyed hair.

Hair treatment agents including: at least one fatty alcohol, at least one cationic surfactant, at least one silicone, at least one organic acid, and phenoxyisopropanol.

Hair treatment agents containing at least one anionic surfactant, at least one amphoteric and/or non-ionic surfactant, at least one cationic polysaccharide polymer, o-phenylphenol and/or salts of o-phenylphenol, at least one organic acid and at least one lipid component reduce or prevent the washout of color from dyed hair.

Hair treatment agents including: at least one fatty alcohol, at least one cationic surfactant, at least one aminofunctional silicone, o-cymen-5-ol, and phenoxyethanol.

Hair treatment agents containing at least one anionic surfactant, at least one amphoteric and/or nonionic surfactant, at least one cellulose-based cationic polymer, at least one amino-functional silicone, at least one organic acid, and phenoxyisopropanol reduce or prevent the washing out of color from dyed hair.

This disclosure relates to a hair treatment agent, comprising at least one fatty alcohol, at least one cationic surfactant other than an esterquat, at least one esterquat, at least one cationic polysaccharide polymer, at least one silicone, and at least one compound of formula (I)

(HCOO.sup.).sub.nX.sup.n+(I)

in which n denotes the number 1, 2 or 3, and X denotes H or a metal ion, and at least one divalent or trivalent metal salts reduces or prevents dye from being washed out of colored hair.

The disclosure relates to hair treatment agents comprising at least one fatty alcohol, at least one cationic surfactant and at least one divalent or trivalent metal salt. At least one organic acid and ethyl lauroyl arginate reduce or prevent dye from being washed out of colored hair.