Diisononylphthalat

Diisononyl phthalate (DINP) is a phthalate ester used as a plasticizer for polyvinyl chloride (PVC). It is the diester of phthalic acid with isononyl alcohols, typically supplied as a mixture of branched isononyl esters. DINP has a high molecular weight and low volatility, which helps PVC retain flexibility over a wide temperature range.

Production and properties: DINP is formed by esterification of phthalic acid (or phthalic anhydride) with isononyl alcohols, followed by purification. It blends well with PVC resins and stabilizers, and its branched alkyl groups reduce crystallization, contributing to durable flexibility. Like other phthalates, DINP can migrate from PVC under heat, prolonged contact with fatty substances, or mechanical stress.

Applications: DINP is widely used in flexible PVC products such as flooring and wall coverings, cables and electrical insulation, hoses, coatings, and packaging films. It is often chosen for its combination of high plasticizing efficiency and permanence. In some applications, manufacturers replace lower molecular weight phthalates with DINP; in others, they seek non‑phthalate or higher‑molecular‑weight alternatives.

Health and safety: DINP is not typically acutely toxic, but animal studies have raised questions about potential developmental and reproductive effects at high exposures. Human risk assessments emphasize consumer exposure from products rather than occupational exposure, with risk depending on dose and exposure route. It is not classified as a carcinogen by major authorities, but health concerns have driven regulatory actions in some jurisdictions.

Regulation: In the European Union, DINP is subject to restrictions for toys and childcare articles under REACH and related directives, with limits on certain uses and migration. Regulatory approaches vary by country, and some applications employ alternative plasticizers.