DIDP and DINP are members of the phthalate family, a group of chemical compounds primarily used to make polyvinyl chloride (PVC), also known as vinyl, more flexible, stable and durable. Phthalates are found in hundreds of everyday products across homes, hospitals, vehicles, and commercial settings. Due to the way phthalate plasticizers interact with the materials they are added to; they remain in the product and are not prone to migrating or evaporating easily.
DINP applications include wire and cable coating, building and construction (vinyl tiles, resilient flooring, PVC-backed carpeting, roofing, wall coverings, etc.), automotive (window glazing, doors, acrylic plastisol sealants in wheel wells, underbody coatings and paints), vinyl clothing (raincoats and boots, gloves, etc.), tool handles, flexible tubes, and hoses. Approximately 5% of DINP is used in non-PVC applications such as rubber polymers, inks and pigments, adhesives, sealants, and paints.
DIDP applications include building and construction (electrical wire coating, vinyl tiles, resilient flooring, PVC-backed carpeting, roofing, wall covering etc.), automotive (upholstery and interior finishes such as synthetic leather for car interior seats and dashboards, undercoating, insulation for wire and cable, window glazing etc.), flexible tubes, profiles, and hoses. Other DIDP applications include use in inks, adhesives, sealants, synthetic lubricants and engine oils.
While they can be employed in a variety of applications, phthalates are not necessarily interchangeable. The characteristics of an individual phthalate often make it well suited to a particular product, allowing manufacturers to meet unique requirements for its use (function and safety specifications), appearance (texture, color, size and shape), and durability and wear.
EPA makes clear that “All risk evaluations, whether EPA-initiated or manufacturer-requested, will be conducted in the same manner.” EPA applies the same rigorous scientific criteria and includes expert peer reviews of its evaluations. A manufacturer-requested risk evaluation allows manufacturers to request that EPA assess the safety of a chemical under specific conditions of use. This process can provide regulatory clarity and certainty for manufacturers and consumers.
In May 2019, ACC’s High Phthalates Panel, representing major producers, importers, and users of DINP, DIDP, and other high molecular weight phthalates, submitted a request for an EPA risk evaluation of DINP and a request for an EPA risk evaluation of DIDP under TSCA.