This study was carried out to observe the extracting characteristics of rubber packing, which were attached to the plastic lunch boxes. 65, Lunch boxes collected from 5 types of marketed products were analyzed measuring pH, evaporation residue, and KMn04 consumption, Lead, Zinc contents.
The influence of solvent and temperature were also studied by extracting with water´, and 4% acetic acid at 60°C´and 90°C.
The results were summarized as follows.
1) The material test showed that the rubber packing of 5 types of products was made from chloroprene rubber, styrene butadiene rubber and natural rubber.
2) _ pH values of aqueous extracts were higher than the pH of control water by 0.87-2.67 at 60°C and 1.58-2.76 at 90°C.
3) Evaporation residues ranged 11.4-2,216.3 ppm and only 1 type of products met standard of synthetic resin products.
4) KMnO4 consumption -ranged 0.8-12.4 ppm and 3 types of products met the standard of synthetic resin products.
5) Leads were detected in 3 types of products and their concentrations ranged 0. 1-22.27 ppm.
6) Solvents influenced the extracts characteristics as the amounts of evaporation residues extracted with 4% acetic acid were higher than those extracted with water.
7) Temperature influenced the extracting characteristics as the amounts-. of evaporation residues extracted at 90°C were higher than hose extracted at 60°C.
|