Environmental Engineering Reference
In-Depth Information
Table 8.4
Some Common Additives in Plastics Used for
Packaging Food and Beverages
Source: Adapted from Sing et al. (2012).
Additive
Example
Function
Antiblock agent Talc, mica, ceramic
spheres
Prevents sticking of films
Antifog additive Sorbitan and
glycerol esters
Prevents condensation inside
package
Antistatic
agents
Carbon and
metallized fillers
Controls static buildup
Antioxidants
Hindered amines,
light absorbers
Controls light-induced oxidation
Biocides
Ethoxylated amines Controls microbial contamination
of package surface
Lubricants and
slip agents
Waxes and amides Ease of processing
Heat stabilizers
Prevents degradation and
discoloration during processing
Plasticizers
Epoxidized oils,
phthalates
Makes the plastic softer and pliable
The kinetics of migration of additives from the package into the (food)
contents depends on the characteristics of the plastics such as density or
free volume, crystallinity, glass transition temperature (Tg), as well as the
polarity, molecular mass, and boiling point of the migrant species.
Migration rates also depend on the temperature, relative humidity, pH
value, and the composition of the food contents (Sajilata et al., 2007). Given
the number of variables that can affect the results, reported data must be
compared cautiously.
It is the differential solubility of these compounds that results in their being
partitioned between the food and plastic, achieving an equilibrium
concentration.
Diffusion of chemicals in and out of the plastic film conforms to Fick's
second law:
