Residual chemicals in silicone rubber products for food contact use

The residues of additives and other chemicals in 23 kinds of silicone rubber products for food contact use, including nipples, packing and spatulas, were investigated by GC/MS. The packing and spatulas contained 80 similar to 480 mug/g of BHT, 60 similar to5,830 mug/g of di(2-ethylhexyl) phthalate (DEHP), and 60 similar to 80 mug/g of dibutyl phthalate, while the nipples contained no additives. All of the samples contained 15 to 20 peaks of polydimethylcyclosiloxanes. Dodecamethylcyclohexasiloxane (D6) to tetratriacomethylcycloheptadecasiloxane (D17) were confirmed, and other larger siloxanes up to pentacontamethylcyclopentacosasiloxane (D25) were estimated. A rough estimate of the total cyclosiloxane content was 3,310 similar to 14,690 mug/g. They might be mainly unreacted materials or by-products, and some of them might be additives. Based on the migration test, no chemicals were released into 20% ethanol at 60 degreesC for 30 min, though DEHP and the polydimethylcyclosiloxanes were released into n-heptane at 25 degreesC for 60 min.