Physically rather than chemically. The plasticiser molecules position themselves between the polymer chains and screen the attractive forces holding them together, so the chains can slide past one another. No reaction occurs, which is why plasticiser can migrate out over time and the article stiffens as it does.
2
Why is DOP restricted?
It is classified in the EU as toxic for reproduction category 1B and as an endocrine disruptor, and it is listed in REACH Annex XIV, so its use requires authorisation. It is separately restricted in toys, childcare articles, food contact materials and medical devices. Supply is conditional on the end use being permitted in the destination market.
3
What replaces DOP?
DOTP, dioctyl terephthalate, is the closest drop-in substitute, being an isomer that performs comparably without the classification. DINP is used where a high molecular weight phthalate is acceptable, and DINCH where a fully non-phthalate option is required. The choice depends on the application and on what the destination market permits.
4
Is DEHP the same as DOP?
Yes in commercial practice. DOP historically meant dioctyl phthalate generically, and the material traded under that name is di(2-ethylhexyl) phthalate, DEHP, CAS 117-81-7. Because the abbreviation is ambiguous, the CAS number should be used when specifying, particularly given the regulatory consequences attached to this specific substance.
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