EPO upholds validity of Lonza's patent on paint containing zinc pyrithione & zinc oxide

摘要

The validity of Lonza's patent EP-0963291 on the use of zinc pyrithione blended with zinc oxide in paint was upheld by the European Patent Office at a hearing on 6 October 2016. Zinc pyrithione (aka zinc omadine or zinc 2-pyridinethiol-1-oxide) has both fungistatic and bacteriostatic properties, ie it inhibits cell division in both fungi and bacteria. It has been used for sundry medical applications, including the treatment of dandruff, psoriasis, vitiligo and various skin conditions, since the 1930s. Arch Chemicals pioneered the use of zinc pyrithione in architectural paints in the early 2000s, claiming that it is useful as an ingredient for interior paints, combatting "sick building syndrome" (allegedly due to the build-up of mould, mildew and bacteria affecting human occupants) and as an ingredient for exterior paints, combatting discoloration by fungi, lichen and algae. Zinc pyrithione has the added advantage of low solubility in water and resistance to attack by ultraviolet radiation, underscoring its contribution to long-term protection. Zinc pyrithione also contributes to dry-film in-can preservation of paint quality. Arch Chemicals (headquartered in Norwalk, CT) was acquired by the Lonza group (headquartered in Basel, Switzerland) for $57 M in October 2011.