Safety assessment of the substance dimethyl carbonate for use in food contact materials
This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) deals with the safety assessment of dimethyl carbonate used as monomer for making a polycarbonate prepolymer with 1,6-hexanediol and then reacted with 4,4′-methylenediphenyldiisocyanate (MDI) and diols, such as polypropylene glycol and 1,4-butanediol, to form a thermoplastic polyurethane containing 29% of the polycarbonate prepolymer. This polymer is intended for repeated use articles with short-term contact (≤ 30 min) at room temperature for types of food, simulated by 10% ethanol and 3% acetic acid. In the third migration test performed at 40°C during 30 min, overall migration was below 2 mg/dm2. Complete migration of the residual dimethyl carbonate would have amounted to less than 1.5 μg/kg food. The migration of two cyclic hexanediol carbonate oligomers was below 50 μg/kg food when determined by the third migration test; that of all others was below 1 μg/kg food. Three in vitro genotoxicity studies performed in accordance with OECD Guidelines and covering the three endpoints gene mutation, structural and numerical aberrations were provided and were considered negative by the CEF Panel. The oligomers detected by the migration tests are formed from dimethyl carbonate and 1,6-hexanediol (FCM ref No 1067) do not give rise to concern for genotoxicity. The CEF Panel concluded that the use of dimethyl carbonate does not raise safety concern in the application described above. It is aware that dimethyl carbonate may be used for other polycarbonates and/or under other conditions. These are likely to result in different migrates which need to be evaluated by the business operators. In such cases, the migration of dimethyl carbonate and the total polycarbonate oligomers below 1,000 Da is of no safety concern, if each of them does not exceed 0.05 mg/kg food.