Oil is Oil...Until its Not

An Investigation into the Coating Structure-Property Relationships of Various Process Oils Process oils are used in a myriad of applications such as coatings, rubber, inks, sealants and carbon black dispersions.1 As these oils are used in a variety of industries, the characterization and nomenclature used is not specific to any of the aforementioned applications. The American Petroleum Institute (API) divides process oils into five categories based on chemistry, viscosity index, sulfur content and type/degree of processing.2 While this information is important, not all of it is immediately pertinent to the coatings formulator. [...]the blend was under-indexed with respect to its NCO: The cloud point is the temperature at which hitherto dissolved solids are no longer completely soluble and precipitate as a second phase, thus providing a cloudy appearance.4 While A-components containing Oils 2 and 11 were stable dur ing storage, it was not until the A- and B-components were combined and cured into a film that incompatibility, manifesting as oil migration, was observed between the process oil and the B-component.