(EN) Powder coatings may be given tribo-charging characteristics by the addition thereto of an additive which comprises aluminium oxide and/or hydroxide which has been sheared such that the additive resulting therefrom is a fine, essentially aggregate-free powder which comprises at least 5 % by weight of particles of maximum particle size 0.2 micrometres. A preferred way of achieving the particle size requirement is to add to the aluminium oxide/hydroxide prior to shearing a proportion of a fine particle extender of maximum particle size 0.2 um. The preferred extender is fumed silica. The additive is simply added to any powder coating composition in a quantity sufficient to confer on it the desired degree of tribo-charging characteristics.
