Redispersible polymer powders are polymer emulsions which have been converted by a series of process such as high temperatures and pressures, spray drying and surface treatment to powdered thermoplastic resin materials. When mixed with water, these powdered organic binders can redisperse in water back into new emulsions with essentially identical properties to the original copolymer emulsions.

The addition of redispersible polymer powders into mortar can increase the cohesiveness, cohesion and flexibility of mortar. First, it can improve the water retention of mortar and form a film to reduce evaporation of water. Second, it can improve the bond strength of mortar.