Training day on program SML Exercises

Exercise 1 Additive migration from a monolayer sheet Goal: searching data base, understanding temperature effect, introduction to partition coefficient

Packaging geometry and layer properties Packaging LDPE, monolayer V = 1000 cm 3 S= 6 dm 2 thickness= 0.5 mm [conc.] =1000 ppm MW = 531 Da Additive : Octadecyl 3-(3,5-di-ter-butyl-4-hydroxyphenyl)propionate CAS#

Problems 1.Approximate the diffusion coefficient at 20, 40 and 80 °C 2.Calculate the time t c to reach the SML of 6 mg/kg 3.What is the apparent effect of the partition coefficient K on t c (compare K = 1 and K = 10)

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K=10

Solutions High K (low solubility in food) increases time to reach SML

Exercise 2 Soft drink contamination by a pigment degradation product Goal: apprehend untypical geometry with surface/volume ratio

C.I. Pigment Red 53 Extrusion at temperature > 150°C produces  -naphtol

Measured concentrations  -naphtol article closure HDPE masterbatch HDPE 190 mg/kg 1 mg/kg concentration 1.Define the simulation geometry for a 1 litre bottle 2.Approximate D at 20°C (MW = 144 g/mol) 3.Calculate the concentration of contaminant after 100 days 4.Concentration in soft drinks was measured at 0.3 mg/kg; conclusion ?

1 2 Closure diameter is 3 cm 3 Surface of closure is only one part of package total surface !!

thickness of closure  -naphtol is quite soluble in water Approximate the diffusion coefficient for a MW of 144 Da in HDPE

D is automatically calculated Select polymer Define MW Select experimental T

Solution Q4 The measured concentration of 0.3 mg/kg cannot be reached with a concentration of 1 mg/kg in the closure. To get such a concentration in soft drink, the starting concentration of ß-naphtol should be > 200 mg/kg in the HDPE closure. This indicates that the closures that contaminate the soft drinks were more contaminated than the ones that were measured. The HDPE closures and masterbatch were sent by the producer months after the soft drink analysis. Probably, ß-naphtol was lost during this storage time (volatility of the molecule).

Exercise 3 Degradation of a clarifying agent in polypropylene Goal: designing multilayer packaging, defining temperature profile

in polymer: 2000 ppm in food (fresh ananas pieces in juice): 200 ppb  cherry taste from 100 ppb

Simulation parameters Geometry: spherical segment (H=5, R=3, D=7, d=4 cm) Multilayer PP-EVOH-PP (thickness= 90, 10 and 200 µm) D PP : E a =48.6 kJ/mol, D 0 = 0.4 cm 2 /s D EVOH : approximate as PA (polyamide); (MW tolualdehyde = 121 Da) Assumption: tolualdehyde is 10X more soluble in EVOH than in PP Concentration in the food contact layer (200µm) is 20 mg/kg

Problems 1.Estimate migration in food for a 3 days shelf life at 5°C 2.Compare multilayer and monolayer packaging 3.Estimate effect of hot filling (100°C, 10 min cooling to 5°C) on the migration

1 2 Define layers thickness, diffusant concentration in each layer and partition coefficient for each interface Enter the Arrhenius parameters for the two PP layers 3 4

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3 layers 3 days at 5°C  migration is mg/kg 1 layer (PP, 200 µm) 3 days at 5°C  migration is mg/kg

3 layers Hot filling + 3 days at 5°C  migration is mg/kg 1 layer (PP, 200 µm) Hot filling + 3 days at 5°C  migration is mg/kg