High Molecular Weight (HMW) phthalates, more simply known as high phthalates, include those with 7-13 Carbon atoms in their chemical backbone, which gives them increased permanency and durability. The most common types of high phthalates include DINP, DIDP, DPHP, DIUP, and DTDP. The European market has been shifting in the last decade from low to high phthalates, which today represent around 85% of all the phthalates currently being produced in Europe.
Western Europe Consumption of Phthalate Plasticisers.
Source: Estimates based on IHS Chemical, Plasticisers Marketing Research Report.
Risk assessment results have shown positive results regarding the safe use of this group of high phthalates. They have all been registered for REACH and do not require any classification for health and environmental effects, nor are they on the Candidate List for Authorisation. High phthalates are not CMR, neither are they considered endocrine disruptors.
The following phthalates are the most commonly used:
• DINP (CAS Nos: 68515-48-0 and 28553-12-0 EINECS Nos: 271-090-9 and 249-079-5)
• DIDP (CAS Nos: 68515-49-1 and 26761-40-0 EINECS Nos: 271-091-4 and 247-977-1)
• DPHP (CAS No: 53306-54-0 and EINECS No: 258-469-4)
They are commonly used in PVC products such as wire and cables, flooring, truck tarpaulins,wallcovering, self adhesive films or labels, synthetic leather, coated fabrics, technical foils, roofing membranes and automotive applications.
These phthalates are produced by esterification of "oxo" alcohols averaging a carbon chain length of nine or ten. The "oxo" route differs from the 2-ethylhexanol route in that the alcohol for subsequent esterification is produced through the hydroformylation of an alkene (olefin) rather than the dimerisation of butyraldehyde. The hydroformylation process adds one carbon unit to an alkene chain by reaction with carbon monoxide and hydrogen under specific temperature and pressure conditions and with the help of a catalyst. In this way a C8 olefin (alkene) is carbonylated to yield a C9 alcohol; a C9 alkene is carbonylated to produce a C10 alcohol.
Due to the distribution of the C=C double bonds in the olefin and differences in catalysts selectivity, the position of the added carbon atom can vary. In such a reaction, an isomer distribution is generally created, with the precise nature of this distribution being dependent upon the precise reaction conditions. Consequently, these alcohols are termed iso-alcohols and subsequently iso-phthalates. The C9 and C10 iso-phthalates are commodity general purpose plasticisers.