Estimation of migration values

In the following Dp-values calculated with the refined Eq. (15-3) and partition coefficients KpF assumed to equal 1 are used for estimating worst case migration rates for additives from polyolefins with Eq. (7-51). These estimated values are compared with experimentally obtained migration values carried out under well defined conditions for several additives from HDPE and different PP-types (Table 15-3a) into olive oil (O Brian et al., 1999 and 2000). The results are summarized in Table 15-3b. 

4 2-(2-Hydroxy-3-t-butyl-5-methyl phenyl)-5-chlorobenzo-tri azole 316 1500 (1400-1670) HDPE 

Tkble I5-3b Measured and calculated migration values [mg/kg] of some additives from HDPE and PP into olive oil. 

The underestimation in the case of the additive with the main component molecular weight 3900 has the same explanation as that given for the 2000 Mr additive in LDPE. It is a mixture of several species with a mass distribution in which the lowest mass provides the highest relative contribution to the overall amount of migration. 

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