ABSTRACT
The main components of powder detergent formulations are surfactants and builders. Heavy-duty laundry powders also often contain bleach systems. The ability to adsorb nonionic surfactants and to provide a free-flowing powder is of increasing significance, especially for highly concentrated compact detergents, making builders an important processing aid. The main requirement for a successful builder is its sequestering or ion exchange capacity with respect to calcium and magnesium. Sodium silicates have traditionally been employed in detergent formulations for many decades: first in combination with soda ash as precipitating builder, later as a source of alkalinity and buffering agent, as dirt carrier, and as corrosion inhibitor. Cogranulates of sodium carbonate and sodium silicate are offered to the market as an easy-to-use material, improving washing efficiency by reducing the amount of detergent required for each load. Traditionally, most powder detergents were produced by spray-drying, the cheapest way of manufacturing large volumes of low-density granular detergents.
