PETpla.net Insider 12 / 2016

COLOURANTS / ADDITIVES 11 PET planet Insider Vol. 17 If we take the example of beer, most types are sensitive to UV radiation and visible light up to 510nm – this results in the ‘Light- struck’ effect or ‘Skunked flavour.’ Both UV light and visible light induce a series of reactions that eventually produce 3-methylbut-2-ene-1-thiol (3-MBT) out of the hop components. 3-MBT has an extremely low taste threshold (4 parts-per-trillion), which means that the smallest amount in beer makes its presence felt (Chem. Eur. J., 2001, 7: 4553– 4561; Cerevisia, 2008, 33(3):133-144). The good news is that proper light protection in combination with an attractive colour makes a big difference for product integrity (as well as brand appeal). A regular amber PET bottle with no light protection may reduce 3-MBT formation to some extent. However, a specifi- cally formulated colourant for PET with light protec- tion above 510nm can reduce 3-MBT formation up to 90%. Many formula- tions from Holland Col- ours are also said to be compatible with monolayer oxygen barrier additives, providing the ultimate combination of product protection and attractive colour. LightGuard series Holland Colours’ Light- Guard series of UV and light absorbers provide specific protection from 370nm up to 400nm in the UV range, and all the way from 400nm up to 700nm for light-sensitive prod- ucts. This is claimed to offer specific protection for all kinds of sensitive prod- uct formulations. If only UV protection is required, this can be combined with any colour. Holland Colours pro- vides calculation models for customers to deter- mine the required dosing level and additive cost as a function of container wall thickness and UV protection requirements. They can also assist with packaging develop- ment and offers analytical support for prototype package performance testing. www.hollandcolours.com