Before detergents, people used simple soaps that did an adequate job of cleaning but left a soapy residue on clothes. If you look at what makes up the average laundry detergent, you find a list of ingredients that may seem mysterious and complex, but all of these ingredients have a specific purpose to help clean clothes efficiently and wash away thoroughly without a soap residue.
Surfactants are compounds that have the ability to both bind with water and attach to grease and dirt, which allows them to loosen dirt and then suspend it in the water, away from the fabric, to be washed away. This works because of the unusual molecular structure of the surfactant, which has a water-attracting pole and a water-repelling pole.
Surfactants hold onto types of dirt and does not easily dissolve in the water. They also break the surface tension between the water and the stain and then pull the dirt away and hold it in the water for rinsing.
Alkylphenol ethothylate is a surfactant.
Binders and Fillers
Builders and fillers add additional power to the surfactants or help with problems caused by particular minerals in the water like calcium or magnesium. Builders connect with calcium or magnesium molecules to keep them out of the way so surfactants can do their job.
Inorganic phosphate is an example of a detergent builder. Fillers help to boost cleaning performance.
Manufacturers add compounds like borax, sodium sulfate and alcohols to produce better cleaning results.
Water helps to keep many of the other ingredients in solution and makes liquid detergents easy to pour. It can compose as much as 12 percent of the product.
Laundry detergent manufacturers add enzymes to their products to help break down stains and grease for removal from the fabric. Amylase, protease and pectinase are examples of enzymes used in laundry detergents.
Dyes and Fragrances
Manufacturers use dyes to make laundry detergents more visually appealing to users and fragrances to make clothes smell clean and mask the odor of chemicals and solvents. Some of these colorants have negative effects on the health of humans and the environment, such as Rhodamine B and some metalized dyes.
FD&C Blue 1 is an example of one of the many detergent dyes.
An array of other ingredients are added to detergents to make cleaning more effective or to enhance the removal of the product. Disodium diaminostilbene disulfonate is an optical brightener found in some detergents.
Sodium hydroxide adjusts the pH of the product for best cleaning results. Silicone polyether helps to lubricate yarns for softness after washing.
The list of ingredients on the detergent label many contain many other ingredients, depending on the product, the brand and the specialized use of the product.