Let’s Talk Wash Chemistry
Let’s Talk Wash Chemistry
When you’re trying to decide what washing products you’re going to use in your commercial laundry, it’s really helpful to understand just what all those different chemicals are and just what they do once they are introduced to the wash cylinder. Today, it’s all about chemistry!
What is a Detergent?
Laundry detergents, whether in powder or liquid form, rely on surfactants as their active ingredients. Surfactants are charged, or “ionic,” molecules with two distinct parts: one interacts well with water, and the other with oils. This dual nature helps lift grease and grime from fabrics and suspend them in water. Surfactants can also create bubbles.
However, dissolved metal salts in water, particularly in “hard” water containing calcium and magnesium, can reduce surfactant effectiveness, leading to soap scum formation. To counteract this, modern detergents include phosphates, water softeners, and metal sequestrants, which prevent soap scum formation. Because phosphates can cause environmental issues like algal blooms, their use in detergents has been reduced. This is also the reason that water softeners are so popular in commercial laundries.
Many detergents also include optical brighteners, which absorb ultraviolet light and emit blue light to create the appearance of brighter whites and colors. Additionally, fragrances are often added for a fresh scent, though they are not essential to cleaning performance. Some detergents also contain enzymes, which will be explained further below.
What Ingredients are in Detergents?
The primary components of laundry powders or solids are salts, such as sodium sulfate, which prevent clumping and add bulk. Sodium carbonate (washing soda) is another common ingredient, helping to break down grease and grime so they dissolve in water.
Powders often include oxidizing agents like sodium percarbonate, a combination of washing soda and hydrogen peroxide, for mild bleaching. Tetraacetylethylenediamine is often added to activate this bleaching effect.
A key advantage of powders is that their components remain separate in solid form, allowing for a more stable formulation. This is why powders typically have visibly distinct granules.
Most modern automatic delivery systems that use solid detergents are only capable of feeding one machine at a time. In a larger laundry, this will require the ability to pause one or more machines when multiple machines are calling for chemicals at the same time. Check with your equipment manufacturer and verify that they have the ability to automatically pause the wash program via a signal from the chemical system. Without it, the solution becomes significantly less elegant.
What Ingredients are in Liquid Detergents?
The main ingredient in liquid detergents is water, with the remaining ingredients carefully formulated for stability and effectiveness. Liquid detergents include surfactants, alkaline salts, metal sequestrants, and water softeners.
Surfactants in liquids can be ionic (charged) or non-ionic (uncharged). Non-ionic surfactants, which are liquid by nature, are better for suspending oils in water and do not form soap scum, making them unsuitable for powders. Liquids also require preservatives to prevent microbial growth.
Unlike powders, liquids do not typically include peroxide-based bleaching agents, which can kill microbes. This absence makes washing machines more susceptible to mold and bacterial transfer. Instead, liquid detergents rely on optical brighteners.
What are Enzymes?
Enzymes are proteins that speed up chemical reactions and target specific stains. For instance, lipase breaks down fats, protease targets proteins, and amylase works on starches and sugars. These enzymes are derived from organisms in cool climates, enabling them to function at typical washing temperatures.
Excessive heat renders them ineffective, meaning cold water washing temperatures between 60-70°F or 15–20°C are ideal.
Powder vs. Liquid: Which is Better?
The choice between powder and liquid detergents depends on factors like performance, cost, environmental impact, and personal preference. Experimenting with different products can help determine what best suits your needs and aligns with considerations like recyclable packaging.
Water is quite dense (8.3lbs/gal or 1kg/liter) and that density affects transportation cost, meaning it’s likely that liquid detergents are more costly than their powdered brethren, as the first ingredient in liquid detergents is typically water. Liquids are somewhat easier to deploy, however, and don’t require overly complicated delivery systems like solid systems do. Solid detergent systems are made up of a “cake” of compressed powdered detergents, onto which water is flushed to create the liquid detergent on site, rather than transporting it.
For example, using a half-dose of a recyclable, enzyme-rich laundry powder at 20°C can be both effective and environmentally friendly.
To learn more about detergent ingredients, ask your chemical consultant, consult product websites or material safety data sheets (MSDS), which detail potentially hazardous chemical contents.
What is Chlorine Bleach?
Chlorine bleach works by using its active ingredient, sodium hypochlorite, to break down stains through a chemical process called oxidation. Sodium hypochlorite in chlorine bleach releases oxygen when it comes into contact with water. This oxygen reacts with the molecules in stains, breaking apart the bonds that give them their color. By altering the molecular structure of the stain, it effectively makes the stain colorless or soluble in water, allowing it to be washed away.
Many stains, such as food, sweat, or grass stains, are organic in nature. Chlorine bleach breaks down the proteins and other organic compounds in these stains into smaller, more water-soluble fragments, which can then be rinsed away during the wash cycle.
Chlorine bleach also kills bacteria, fungi, and viruses, which is an added benefit for sanitizing laundry. This is especially useful for cleaning items like towels, bedding, and clothing exposed to germs.
Important Considerations:
Fabric Safety: Chlorine bleach is strong and can weaken or discolor delicate or non-white fabrics. Always check the care label and do a spot test.
Avoid Mixing with Other Chemicals: Never mix chlorine bleach with ammonia or acidic cleaners (like vinegar), as this can release toxic chlorine gas.
Effectiveness on Different Stains: Chlorine bleach is most effective on white fabrics and stains that are oxidizable, such as wine or coffee, but less effective on grease or oil-based stains.
By understanding its mechanism and proper use, chlorine bleach can be a powerful ally in removing stains and sanitizing laundry.
What is Non-Chlorine Bleach?
Non-chlorine bleach, also known as oxygen bleach or color-safe bleach, works by using oxidizing agents to break down stains and brighten fabrics without the harshness of chlorine bleach. Its active ingredient is usually hydrogen peroxide or compounds that release hydrogen peroxide, like sodium percarbonate or sodium perborate. Non-chlorine bleach releases oxygen when dissolved in water. This oxygen interacts with the molecules in stains, breaking down their structure and making them colorless or water-soluble. This process works effectively on organic stains such as coffee, tea, wine, or sweat.
Unlike chlorine bleach, which can damage or discolor fabrics, non-chlorine bleach is gentler and safe to use on most colored or delicate fabrics. It doesn’t strip dyes but instead enhances brightness by removing dinginess caused by stains or residue. By oxidizing and removing stains, it improves the overall appearance of garments without the risks associated with chlorine bleach.
Hydrogen peroxide, the active ingredient in most non-chlorine bleaches, also has mild antibacterial properties. While not as potent as chlorine bleach, it can still help reduce bacteria and odors on fabrics. Non-chlorine bleach is often considered a more eco-friendly alternative to chlorine bleach because it breaks down into water and oxygen after use, leaving fewer harmful byproducts.
Non-chlorine bleach is excellent for light stains and general brightening but may not be as effective on heavy or stubborn stains as chlorine bleach. It’s also generally safe to use on most fabrics, but always check care labels for specific instructions. Non-chlorine bleach often works best in warm or hot water, as heat activates the oxygen-releasing compounds.
What is Fabric Softener?
Fabric softeners work by coating the fibers of fabrics with a thin layer of chemicals that alter their texture and reduce static electricity. Fabric softeners contain cationic surfactants, which are positively charged molecules. These molecules bind to the negatively charged surfaces of fabric fibers, creating a smoother surface. This coating reduces the stiffness of the fibers, making them feel softer to the touch.
Static cling occurs when fabrics rub together (a typical occurrence in a tumble dryer, where the humidity is low), causing an accumulation of static electricity, especially in synthetic materials like polyester. The coating provided by fabric softeners neutralizes the charge on fabric fibers, minimizing static buildup and making garments easier to separate after washing or drying.
The lubricating effect of fabric softeners reduces friction between fibers, which can make clothes easier to iron and help them resist wrinkling. This coating can also help maintain the texture of delicate fabrics over time. However, fabric softeners reduce the absorbency of towels and other goods because of the residue left which interferes with the fibers of the goods ability to come into contact with moisture.
What is Laundry Sour?
Laundry sour chemicals, often referred to simply as “sours,” are used in commercial and industrial laundry processes to neutralize alkaline residues and maintain fabric quality. Detergents, bleach, and other laundry chemicals are typically alkaline (high pH) to enhance cleaning. However, if these alkaline residues are left on fabrics, they can cause skin irritation, contribute to fabric wear and tear over time, and lead to yellowing or discoloration.
Laundry sours are acidic chemicals (low pH), such as acetic acid or citric acid, that counteract these alkaline residues. By neutralizing the pH, sours leave the fabric at a skin-friendly and fabric-safe pH level. If left in the goods, alkaline residues can make fabrics feel stiff. By neutralizing these residues, sours restore a softer texture to fabrics, enhancing comfort.
In regions with hard water, minerals like calcium, magnesium, or iron can interact with alkaline residues, causing deposits or discoloration (e.g., yellowing). The acidic nature of sours helps dissolve and prevent these deposits, keeping fabrics bright and clean.
Prolonged exposure to high alkalinity can degrade fibers, leading to brittleness and damage over time. Sours protect fabrics by ensuring a balanced pH, which reduces chemical stress on the fibers.
Proper dosing is critical, as overuse can result in overly acidic fabrics, which can also cause damage or irritation. Also ensure sours are compatible with the detergents and other chemicals used in the laundry process (your chemical representative should cover this).
Laundry sours are essential for achieving high-quality, residue-free results in professional laundry operations.
Conclusion
Modern wash chemistry is both safe and powerfully effective when used properly and expertise is required to do so. Improper dosing of any of the above chemicals can cause issues not only in the washer, but in subsequent processes like drying and ironing. These chemicals must also be respected when handling, as they can cause injury if they come into direct contact with the skin. Proper PPE is essential when handling laundry chemicals.
