Analysis of saturated and aromatic hydrocarbons migrating from a polyolefin-based hot-melt adhesive into food

ABSTRACT

Hot-melt adhesives are widely utilised to glue cardboard boxes used as food packaging material. They have to comply with the requirements of Article 3 of the European Framework Regulation for food contact materials (1935/2004). The hot melt raw materials analysed mainly consisted of paraffinic waxes, hydrocarbon resins and polyolefins. The hydrocarbon resins, functioning as tackifiers, were the predominant source of hydrocarbons of sufficient volatility to migrate into dry foods: the 18 hydrocarbon resins analysed contained 8.2–118 g kg^–1 saturated and up to 59 g kg^–1 aromatic hydrocarbons eluted from GC between n-C₁₆ and n-C₂₄, substantially more than the paraffinic waxes and the polyolefins. These tackfier resins, especially the oligomers ≤ C₂₄, have been characterised structurally by GC×GC-MS and ¹H-NMR spectroscopy. Migration into food was estimated using a simulating system with polenta as food simulant, which was verified by the analysis of a commercial risotto rice sample packed in a virgin fibre folding box sealed with a hot melt. About 0.5–1.5% of the potentially migrating substances (between n-C₁₆ and n-C₂₄) of a hot melt were found to be transferred into food under storage conditions, which can result in a food contamination in the order of 1 mg kg^–1 food (depending on the amount of potentially migrating substances from the hot melt, the hot melt surface, amount of food, contact time etc.). Migrates from hot melts are easily mistaken for mineral oil hydrocarbons from recycled cardboard.

KEYWORDS:

• Petroleum hydrocarbon resins
• online HPLC-GC-FID
• food contact materials
• oligomers
• mineral oil hydrocarbons
• polyolefin oligomeric hydrocarbons
• comprehensive two-dimensional GC (GC×GC)

Additional information

Funding

The authors acknowledge the financial support of the project and the contribution of raw materials by H.B. Fuller (Lueneburg, Germany).