Napped Artificial Leather Dark Color via Carbon Black Binder

The patent introduces a binder as an intermediary substance that mediates between the disperse dye and the polyester ultrafine fibers. The binder contains specific functional groups (carboxyl, hydroxyl, or amino groups) that enable strong adhesion to the dye particles, preventing color migration while maintaining dark color development. This intermediary binding mechanism resolves the contradiction by providing a stable connection that prevents dye transfer without compromising color depth.

The patent creates a composite coloring system combining disperse dye particles with a binder substance on the fiber surface. This composite approach allows the dark color development of disperse dye to be achieved while the binder provides protective functionality against color migration and improves light resistance. The composite material formed on the fiber surface simultaneously delivers both desired properties.

The patent uses a binder as an intermediary that adsorbs disperse dye particles onto the fiber surface without requiring cationic modification of the fiber itself. This intermediary binding approach prevents direct chemical interaction between dye and fiber that would weaken the fiber structure, while still achieving excellent color migration resistance through the binder's adhesion mechanism.

The patent applies coloring and binding functionality locally on the fiber surface rather than modifying the entire fiber structure. The binder and dye are concentrated on the surface layer, allowing the bulk fiber material to maintain its original strength properties. This local application prevents the two-color impression by ensuring uniform surface coloring without affecting the fiber's internal structure.