Byk -321 Polyether modified methylalkylpolysiloxane copolymer BYK Chemie Defoamer / Antifoaming agent >> Silicone Flow / Levelling agent >> Silicone Scratch/ Srcub/ Mar resistance agent >> Silicone-based Slip control >> Silicone Coatings >> Solventborne Coatings >> Waterborne Butoxyethanol Immiscible in water Solution of a polyether modified methylalkylpolysiloxane copolymer. Silicone levelling additive with defoaming action. It improves the surface properties of solvent-based coatings, with particular emphasis upon levelling. Causing only a slight surface tension reduction, in contrast to most silicone additives it does not stabilize foam and can even impart defoaming action. BYK®-321 is suitable for both solvent-based and aqueous systems. It increases surface slip and thus improves scratch and mar resistance. Formation of Bénard cells is prevented and orientation of flatting agents is improved. BYK®-321 is based on the same active substance as BYK®-320 but cut in a different solvent. It is only available in the North American market. Solution of a polyether modified methylalkyl polysiloxane copolymer. Used in coatings. Provides a slight reduction of surface tension. Offers defoaming action. Exhibits increased surface slip. Imparts improved scratch and mar resistance. Prevents formation of Bénard cells.