Method for dyeing moulded parts made from a polymer

A method for dyeing a molded part produced in a 3D printing process with a polymer, wherein the method comprises:

• a dyeing step (FS) for dyeing the surface of the molded part with a dye, and
• a first post-treatment step (NBS1) for fixing the dye which has penetrated the surface of the molded part, wherein the first post-treatment step is carried out after the dyeing step,
• wherein, in the dyeing step,
• the molded part is placed in a dye solution, wherein the dye solution comprises
• a dye, and
• water, preferably deionized water,
• wherein the dye is introduced into the material of the surface of the molded part, and
• the dye solution is heated, and,
• in the first post-treatment step,
• the molded part dyed in the dyeing step is placed in a first fixing solution, as a result of which the dye introduced into the material of the surface of the molded part is fixed, wherein the first fixing solution comprises
• a polyphenol, an acrylic-based syntan compound, or a synthetic condensation product of aromatic compounds, in particular phenols or naphthalenesulfonic acid, with formaldehyde or urea, and
• water, preferably deionized water, and
• the first fixing solution is heated.