SOLVING FILM DEFECTS WITH SURFACE TENSION MODIFIERS Taking the Mystery Out of 'Pixie Dust'

摘要

Formulators face many challenges when developing new products or supporting older product lines. Film defects like air entrapment, crater formation, poor flow and leveling, substrate wetting, pinholes and crawling are just some of the problems encountered after the binders and pigments have been optimized. The term "pixie dust" is given to a myslical chemical that when added to a coating will fix one or more of the above problems, but the exact mechanism is not known. Chemists have long relied on the trial and error method of tweaking their formulas with a myriad of additives in the hope that one or more will work. The available information about these additives is usually veiled in secrecy or labeled with generic chemical names. In this article we will provide information about identifying the root causes of some of these film defects, how additive manufacturers have developed strategies to modify the surface tension of liquid coatings, and how the formula-tor can make intelligent choices and thereby reduce the number of products to test.