BYK 1691 SD is a solid, highly efficient VOC- and silicone-free polymer defoamer that is commonly used as an additive in various mineral binder systems. BYK 1691 SD shows consistent and effective defoaming over extended periods of time while also improving leveling and surface properties of end products. As a solid formulation, BYK 1691 SD is easy to incorporate into powder-based systems. It efficiently disperses in water to provide long-lasting defoaming without negatively impacting other properties. BYK 1691 SD is particularly suitable for applications that require a smooth, uniform appearance and extended workability windows.