Anionic
coloring agents comprising at least one spacer-arm bounded to their
chemical structure, wherein said anionic
coloring agents have the following formula: CA—RSA, wherein, CA is an anionic coloring agent comprising at least a
chromophore group selected from the group consisting of azo,
anthraquinone, formazane, dioxazine,
phthalocyanine and / or sulphur; and RSA is said spacer-arm, which has the following
chemical structure: —X—R-Z, wherein, X is a
chemical bond or a group having the formula —S(O)n, wherein n is 1 or 2; or a —NR1— group, wherein R1 is a
hydrogen atom or a linear or branched C1-C10
alkyl group; R is a linear or branched C1-C10 alkylene group; Z is a —NR2R3, —S—SO3R4, or —SO3R5 group, wherein, R2, R3, R4 and R5 are, independently, a
hydrogen atom or a linear or branched C1-C10
alkyl group; or, Z is a —NR6—(CH2)m—W group, wherein, R6 a
hydrogen atom, a linear or branched hydroxy C1-C10
alkyl group, or a linear or branched C1-C10 alkyl group; m is an integer from 1 to 10; and W is a —COOR7, —CONR8R9, —SO3H, —S—SO3H, —CN, —SO3R10, or —S—SO3R11 group; wherein, R7, R8, R9, R10 or R11 are, independently, a
hydrogen atom or a linear or branched C1-C10 alkyl group; provided that when X is a —NR1— group, and Z is a —NR2R3 group, then R1, R2 y R3 cannot be simultaneously a
hydrogen atom. The invention also refers to coloring compositions, which comprise at least one anionic coloring agent of the formula: CA—RSA, wherein, CA and RSA are as described above, and an eventual suitable carrier; and coloring compositions comprising at least two
coloring agents, wherein at least one of said coloring agents is an anionic coloring agent as described above, and an eventual suitable carrier. Moreover, the invention reveals the use of the anionic coloring agents and coloring compositions as described above to dye cotton, nylon,
wool,
regenerated cellulose, leather, and
cardboard and paper substrates; and the above dyed substrates. The introduction of spacer-arms in the
chemical structure of anionic coloring agents leads to modified anionic coloring agents, which differ from the known coloring agents in their dying properties such as strength, tone and affinity, due to fixation modifications onto the substrate to be dyed.