Laundry detergents have come a long way since the first bar soaps made from animal fat and lye were offered for sale in the 1700s. The introduction of synthetic detergents to the marketplace in the 1950s offered homemakers more options of fabric care. But it was the 1970s that brought the most significant innovation in laundry, the addition of enzymes that “attack” specific types of stains. It is those enzymes that separate the men from the boys when it comes to clean laundry.
Basic Detergent laundry detergents Formulas
Every detergent manufacturer has secret ingredients and mixtures to produce their specific brands. Many of these ingredients can be manufactured from plants; others are petroleum-based. It is the amount of each ingredient and how they are combined that affects the cleaning ability of the detergent.
Alkalies, a major component in most laundry detergents, are soluble salts and a base which reacts with an acid to neutralize it. They are effective in removing dirt and stains from fabric without excessive rubbing. Soluble salts of an alkali metal like potassium or sodium are good grease removers. They form an emulsion of the oily or solid particles that are held in suspension in wash water to be rinsed away.
The first soap and detergent makers used plant ashes to produce alkalis. Today they are chemically produced by running electricity through salt water to produce sodium hydroxide (NaOH) or caustic soda and potassium hydroxide (KOH) or caustic potash. These are the most commonly used alkalies in soaps and detergents.
Alkaline substances vary in their strength with the strongest causing burns and internal injuries if swallowed. Strong alkalies can also damage fabrics and leave clothes feeling rough to the touch.
- Mild alkali is baking soda (sodium bicarbonate)
- Moderate alkalies include household ammonia, borax, and trisodium phosphate (TSP)
- Strong alkalies include washing soda (sodium carbonate) and lye (caustic soda)
Surfactants and Anti-Redepositing Agents
Surfactants are one of the major components of laundry and cleaning products. They break up stains and suspend the dirt in the water to prevent redeposition of the dirt onto the surface. Surfactants disperse dirt that normally does not dissolve in water.
They work like an oil and vinegar salad dressing. They do not mix unless shaken vigorously in the bottle and they separate almost immediately afterward. The same is true when washing clothes. Surfactants “shake up” the soil which normally does not dissolve in water, making it dispersible and able to be removed with the wash water.
In anionic surfactants, the head of the molecule is negatively charged. This particular type of surfactant is very good at removing oily dirt and stains unless used in water that is full of minerals like calcium and magnesium. The minerals keep the anionic surfactant from working properly. You’ll see anionic surfactants listed as alkyl sulfates, alkyl ethoxylate sulfates, and soaps in the ingredient list.
If you have hard water, you will get better cleaning results with a non-ionic surfactant. These surfactant molecules have no electrical charge. You’ll find these surfactants listed as ethers of fatty alcohols on the label. You may find them combined with anionic surfactants to complement and boost cleaning action.
Types of Surfactants
- alkyl sulfates (anionic)
- alkyl ethoxylate sulfates (anionic)
- ethers of fatty alcohol (non-ionic)
Functional Materials in Laundry Detergent
- pH modifiers to balance acids and bases in water
- optical brighteners (bleach alternative) to improve the appearance of whiteness by absorbing UV light and giving off a blue tint
- water conditioners to manage hard water and inhibit dye transfer
- suds control with soap or silicone to prevent excess foaming
- preservatives to prevent microbial growth
Enzymes can be natural or processed chemically. Different enzymes target specific soils and the catalytic action breaks the soil into smaller molecules to be washed away.
- protease – degrades protein based soils
- amylase – degrades starch based or carbohydrate soils
- cellulase – breaks down cotton fibers to release soils
- lipase – degrades fat-based soils
- mannanase – degrades food-based stains
- pectinase – degrades fruit-based stains
Enzymes are naturally occurring; they help bread rise faster and increase wine yields. The introduction of enzymes into laundry detergents dramatically changed how we do laundry. Enzymes allow us to use lower water temperatures and less detergent to get clothes clean. For many, many years the only way to achieve clean laundry was to use boiling water and harsh lye-based soaps.
Today, scientists have created industrial biotechnology or “white biotech”, which uses enzyme cells or components of cells to generate industrially-useful enzymes for laundry detergents. Industrial biotechnology has the potential to save the planet up to 2.5 billion tons of CO2 emissions per year and support building a sustainable future, according to a report from the World Wildlife Fund,