http://www.nzic.org.nz/ChemProcesses/detergents/11A.pdf
Step 1 - Soap premix manufacture Liquid detergent contains soap as well as synthetic surfactants. This is usually made first as a premix, then other ingredients are blended into it. This step simply consists of neutralising fatty acids (rather than fats themselves) with either caustic soda (NaOH) or potassium hydroxide. Step 2 - Ingredient mixing All ingredients except enzymes are added and mixed at high temperature. The ingredients used in liquid detergent manufacture are typically sodium tripolyphosphate, caustic soda, sulphonic acid, perfume and water. The functions of these ingredients has been covered above. Step 3 - Enzyme addition The mixture is cooled and milled, and the enzymes added in powder form.
Liquid detergent manufacture