Diisononyl Phthalate (DINP)

About This Product

Diisononyl phthalate, DINP, is a general-purpose plasticiser for flexible PVC. It is the ester of phthalic anhydride and isononanol, a mixture of branched C9 alcohols, so the product is a mixture of isomers rather than a single compound. It is traded under two CAS numbers, 28553-12-0 and 68515-48-0, depending on the alcohol route, with an approximate formula of C26H42O4. It is a clear, practically colourless, oily liquid with low volatility. Compared with DEHP, DINP's longer alkyl chains give lower volatility, better resistance to extraction and a slightly lower plasticising efficiency, so a little more is needed for the same hardness. It remains one of the most widely used plasticisers where its regulatory status allows, because it processes easily, fuses well in plastisols and offers a good balance of cost and performance. Its main alternatives are DOTP, a terephthalate, and DINCH, a hydrogenated equivalent. DINP is used in PVC flooring and wall coverings, in wire and cable compounds, in calendered film and sheet, in synthetic leather and coated fabrics, in automotive interior and underbody plastisols, in hoses, profiles and gaskets, and in roofing membranes. In plastisols, its viscosity and fusion behaviour suit spread coating, dipping and rotational moulding. It is also used as a plasticiser in some sealants and adhesives. A DINP specification normally covers ester content, Pt-Co colour, acid value, water, density at 20 °C and flash point. For cable applications, a volume resistivity limit is normally added, and for plastisols, viscosity may be specified. Check each batch certificate of analysis against the agreed limits. Regulation is the key point for DINP. Under EU REACH Annex XVII entry 52, mirrored in UK REACH, DINP is restricted to 0.1% by weight in toys and childcare articles that can be placed in the mouth by children, so it is not used in those articles. Check the current CLP classification and any Candidate List status in the safety data sheet, because both have been under review, and confirm the rules for food-contact articles in your market. An importer into the EU or Great Britain should confirm which registration covers the import and use. DINP is generally not regulated as dangerous goods for transport, but check section 14 of the safety data sheet. Store DINP in closed drums, IBCs or tanks in a dry area, away from strong oxidisers. It is stable under normal conditions, but long exposure to heat and air can raise colour and acidity. Mild steel or stainless steel is suitable for storage. When you enquire, state the application, the end market and its restrictions, the limits for ester content, colour and acid value, any cable or plastisol requirement, the pack format, your annual volume and the destination.