The additive
enables a better heat transfer to the polymer during stretching
of the PET preforms into final PET bottles. In the PET matrix
TiN exists as aggregates and agglomerates with diameters
between 100 and 500 nm (EFSA, 2012) consisting of primary
spherical particles with a diameter of approximately 20 nm. A
safety evaluation of nanoscale TiN was performed by the
European Food Safety Authority (EFSA) based on migration
measurements on PET bottles with 20 mg kg1 TiN in the
polymer and very conservative calculations of the potential
migration. It was concluded that no exposure of TiN can be
expected under the intended conditions of use (EFSA, 2012).
Therefore TiN was included in the positive list with the
restriction to be used only in PET bottles at concentrations up
to 20 mg kg1.