ISO 177:2016 specifies a method for the determination of the tendency of plasticizers to migrate from plastics in which they are contained into other materials or other plastics when they are brought into close contact. NOTE 1 The surfaces into which the migration can proceed can also consist of organic surface coatings, such as lacquers. This test is suitable a) for evaluating the tendency displayed by plastics, particularly in the form of films and sheets, to lose certain of their liquid constituents when they are brought into contact with materials that have an affinity for plasticizers, and b) for studying the tendency to migrate of plasticizers contained in a resin or a series of resins, in one or more concentrations. In case b), standard compounds are prepared on the basis of a well-characterized resin with well-defined ratios of plasticizer to resin. NOTE 2 When the absorbent sheets themselves contain a substance capable of migrating, simultaneous migrations can occur from the test specimens into the absorbent sheets and vice versa. The results may also be affected by the migration of other constituents of the plastic material (for example, oligomers) or by the loss of any volatile constituents other than plasticizers from the plastic material or the absorbent layer.