Process oils are used in a myriad of applications such as coatings, rubber, inks, sealants and carbon black dispersions.
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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.
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While this information is important, not all of it is immediately pertinent to the coatings formulator. Conversely, information pertaining to coatings performance is absent. The dilemma is not the fault of the oil vendor or the formulator. Rather, the oil vendor has a responsibility to its diverse customer base, and to some degree the industry as a whole, to ensure that specifications, testing and nomenclature are as standardized as possible.
The goal of this study was to understand how the properties of process oils (15 naphthenic and one paraffinic) influence the coating properties of a two-component aromatic urethane system. Techniques common to polymer/coatings chemists were used to elucidate the structure-property relationships between process oils and their impact in coating performance.