Leather dye

Leather dyes are dyes that have an affinity for leather and are used for coloring leather. They can be divided into two categories according to the type of solvent: water-insoluble dyes and water-soluble dyes. The water-insoluble dye includes: a sulfurized dye dissolved in an aqueous solution of a sulfide; an oil-soluble dye dissolved in a fat; an alcohol-soluble dye dissolved in an alcohol. Water-soluble dyes include: anionic acid dyes, direct dyes, special dyes for dyeing leather; amphoteric metal complex dyes, sulfited triphenylmethane dyes; cationic basic dyes. Leather dyes can be divided into two broad categories by solvent type: water-insoluble dyes and water-soluble dyes. The water-insoluble dye includes: a sulfurized dye dissolved in an aqueous solution of a sulfide; an oil-soluble dye dissolved in a fat; an alcohol-soluble dye dissolved in an alcohol. Water-soluble dyes include: anionic acid dyes, direct dyes, special dyes for dyeing leather; amphoteric metal complex dyes, sulfited triphenylmethane dyes; cationic basic dyes. The dyeing of leather is divided into two types: dip dyeing and surface coloring (including finishing and spraying). The dyes suitable for leather dyeing are D series; the dyes suitable for leather spray coloring are SP series. The aniline leather and nappa leather, which are popular in recent years, are light leathers that are only slightly coated or unfinished. It is required to be well combined with leather fibers, with high fastness and good levelness and color. Garment leathers also require dyes with good resistance to dry cleaning (solvent). The front leather for shoes is usually painted with pigments, only the surface is colored, while the garment leather is completely dyed, and the cuts are consistent with the color of the surface. Leather dyeing mainly uses acidic and direct dyes, sometimes alkaline, mordant, oil-soluble and reactive dyes, mostly selected from textile dyes. With the improvement of living standards and the development of science and technology, the requirements for dyes for leather have also been correspondingly improved. The requirements for light, abrasion and dry cleaning solvents of garment leathers are higher, in order to maintain the "natural appearance" of the leather surface, The so-called "aniline leather" which is dyed only with synthetic dyes without pigment coating has set new requirements for leather-specific dyes. Metal complex dyes play an important role in leather dyes.