VTT develops fully recyclable coating for packaging
Thin coating considerably reduces the need for aluminium
The Finnish VTT Technical Research Centre has developed an environmentally-friendly packaging coating solution that is especially suitable for pharmaceutical packaging.
The basic materials of aluminium oxide coating are usually trimethyl aluminium and water. The coating is produced using the atomic layer deposition (ALD) method, and offers a new method for manufacturing fully recyclable, thin, light and air-tight packaging materials with excellent gas permeation resistance. To date, the method has been used primarily as a part of the manufacturing process of technical products in semiconductor industry.
The ALD technology, which was developed in Finland in the 1970s, has been utilised mainly in microelectronics to date. It facilitates the manufacture of packaging materials that are thinner, lighter and better sealed than traditional barrier materials. By reducing the use of aluminium by between 500 and 1,000-fold compared with current blisterpacks, the packs are fully recyclable.
ALD coatings are thin, conformal and pinhole-free and they closely follow the contours of the coated material. Their thickness can be adjusted to the accuracy of one atomic layer. Thanks to the thinness of the film (approx. 25 nanometres), the protective layer is bendable and flexible. Furthermore, by using ALD coating, different functions can be integrated in the packaging material, such as properties to prevent water, oxygen, humidity, fats and aromas from permeating the packaging.
Other thin film methods can also produce thin coatings; however, their gas permeability is higher and the material is stiffer and breaks easily. With these competing methods, comparable gas permeation resistance is possible only if thicker films are used.
