Formulation of printing inks

Although they take the form of an apparently homogeneous liquid, printing inks are a complex mixture of constituents of very different natures. They must meet specifications that depend on the printing process, the drying method, the nature of the printing substrate (compatibility, adhesion...) and other specific constraints: printing in one or more colors, subsequent varnishing or coating, in-line or off-line finishing, environment, safety, health, photochemical resistance, resistance to humidity, high or low temperatures, acids, solvents...

Inks can be subjected to a variety of stresses, resulting in a wide range of ink types. There is no such thing as a multi-purpose ink, even for a given process. An ink formulation is therefore often the result of a technical-economic compromise.

After a general description, this dossier presents pigments and colorants, which are common to all inks. Then, as each printing process has its own type of ink, an entire paragraph is devoted to a brief description of each printing technique and a detailed study of each corresponding type of ink.

The inks presented here can be used to print on cellulose substrates (paper and cardboard), but also on polymer substrates (in the form of films, plates or three-dimensional objects), metal substrates (in thin sheet, plate or shaped form) and textiles.