Defoamer

This behavior can be critical either during the adhesive formulation step or during adhesive application. For example, if gravure rolls are used for the application of an water based adhesive the occurrence of foam leads to reduced productivity and therefore higher production cost. Moreover, a strong foaming adhesive most likely will not meet the product specifications such as the required adhesion forces, transparency of the adhesive films or a defect free coating. Therefore, the control of foam phenomena is essential.
Two major foam types can be distinguished: microfoam and macrofoam. The occurrence of both foam types results in insurmountable difficulties during the production or application of the adhesive. Therefore, defoamers are used either to suppress the formation of foam or to effectively destroy foam bubbles once they are formed. To meet the specific demands of each adhesive application Evonik provides a number of different antifoams.