US Patent No. 10,300,002 B2 (Konstantin Goutsis, Gabriele Weser); Henkel AG & Co.
, Duesseldorf, has patented a composition for dyeing keratinous fibers. The composition contains water; and organic solvent comprised of propylene carbonate and benzyl alcohol). The cosmetic composition has a pH value in the range from about 1.0 to about 5.5; at least one acid directly absorbed dye, and at least one nonionic ethoxylated surfactant selected from the group of ethylene oxide adducts to saturated or unsaturated, linear or branched fatty alcohols and fatty acids and to glycerol fatty acid esters, each with about two to about 60 moles ethylene oxide per mole fatty alcohol or fatty acid or glycerol fatty acid esters, and combinations thereof.