The patent sets out a paper product comprising a paper substrate and a barrier coating with an alcohol-based binder and an inorganic particulate. The paper substrate could be coated or printed with the barrier coating composition.
In tests conducted, mineral oil transmission through the barrier coating found reduction in measured infrared (IR) intensity at 2920cm is less than 1%, as determined by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy with the method described in the patent.
The Joint Expert Committee on Food Additives (JECFA) recommends a maximum Acceptable Daily Intake (ADI) of medium and low viscosity mineral oils of 0.01 mg/kg.
Details of composition
The firm said an inorganic particulate could be an alkaline earth metal carbonate or sulphate and listed calcium carbonate, magnesium carbonate, dolomite and gypsum as an example.
The alcohol-based binder may comprise primary, secondary and/or tertiary alcohol groups, which may be attached to a polymer backbone, detailed the patent.
Imerys Minerals said its Pigments for Paper and Packaging segment was paying increasing attention to helping customers develop speciality products for recycled fibre-based packaging.
Inventors Janet Preston, Graham O’Neill and Jonathan Phipps said a problem with current methods is cost and environmental impact.
They said the use of recycled fibre in food packaging in Switzerland is banned but it is used extensively elsewhere and the infrastructure is already in place to recycle fibres.
“Further, the increased use of virgin fibres is environmentally unattractive. The cost is also higher with virgin fibre owing to increased use of water and energy associated with the processing of wood.
“Another solution proposed is to reduce or eradicate mineral oils from printing inks or to pre-treat the waste materials to reduce or remove mineral oils prior to re-use. Again, however, this will have the effect of increasing costs.”
The inventors said a possible solution was to minimize the migration of mineral oil into food through the use of barriers.
“To date, paper, polyethylene and propylene liners have been found not to work or not to work efficiently.
“Other proposals include the use of PET and aluminium foil liners. However, the use of such water-vapour impermeable foils may lead to increased germ formation and, further, it is has been suggested that the direct contact of food and aluminium may present other adverse health risks.”