In our new series of specialist posts, our resident chemistry expert, Iain Coleman, answers a popular customer question:
"What are all your chemicals for?!"
Hydrofinity has reduced the requirement for wash chemicals by adding polymer XOrbs™ to the wash process. However, small volumes are still needed to ensure that quality is of the highest standard. The Hydrofinity chemical suite consists of six different types of chemical including: detergent, emulsifier, bleach, destainer, booster and sour. Why do we need this many? This is a question our customers regularly ask us and rightfully so! Let’s take each chemical on its own merits.
Now here’s a shock - washing clothes with water will not remove stains effectively. Believe it or not, water is a poor wetting agent! This is where detergents come to the rescue. They contain surfactants which improve wetting properties. Water begins to do its job far more effectively once it can wet and penetrate fibres. It solubilises water-based stains so that they can be removed with ease.
Detergent contains suspending agents as well. These agents work together to form a spherical structure called micelles. They surround, suspend and carry away stains that have been removed from the fibres. In this way, they prevent redeposition of the stain onto the fabric so a great detergent can keep your whites looking white for longer!
Furthermore, our detergent contains enzymes which speed up the breakdown of protein and starch-based staining. Enzymes catalyse this process at low temperatures, so they enable our detergent to be just as effective without using more energy!
Stain Types: Grass, Blood, Egg, Sweat, Pasta, Potato
Oil and water don’t naturally mix, they’re said to be immiscible. However, there are numerous examples where stable mixtures can be made, like milk and mayonnaise. Well, these are emulsions and they couldn’t exist without an emulsifier. They stabilise oil and water mixtures that would otherwise separate.
So why is this helpful in laundering clothes? Emulsifiers can form emulsions with different oil types in water which can then be diluted and drained away. Unfortunately, adding an emulsifier to the wash doesn’t remove every single oil that could be present. If only life was that simple! The right emulsifier must be selected for the right oil. This is determined by the hydrophilic-lipophilic balance or the HLB range.
The HLB range is a measure of solubility. Molecules with a low HLB value are fat-soluble and molecules with a high HLB value are water-soluble. For example, effective emulsification of vegetable oil requires an emulsifier with an HLB value in the range of 7-8 and effective emulsification of petroleum oil requires an emulsifier with an HLB value in the range of 10-12. The emulsifier that we use forms stable emulsions in the high HLB range.
Stain Types: Mineral Oils, Petroleum Oils, Spa Oils, Fatty Acids
Have you ever had a stain that just won’t budge? That’s because these stains can’t be removed conventionally. All is not lost, these coloured stains can be turned colourless in the presence of bleach. Sodium hypochlorite is the most commonly used bleach. It’s known as an oxidising agent because it’s oxygen in the bleach that reacts with dye in the stain to make it colourless.
There are many benefits to using sodium hypochlorite including:
- It acts as a chemical disinfectant for bacteria and viruses
- It will bleach effectively in cold water
- It whitens natural fibres like cotton
Despite its many advantages, it’s a very aggressive type of bleach! It will react with coloured clothing the same way it reacts with stains which is why it can leave white spots. Hydrofinity machines will only use small volumes of sodium hypochlorite in wash programs reserved for whites. We use a different kind of bleach for coloured garments…
Stain Types: Vegetable Dye, Tea, Coffee, Red Wine
Oxygen-based bleach or destainers are safe to use on many fabrics. Hydrogen peroxide is the most commonly used oxygen-based bleach.
It reacts with stains in a very similar way to chlorine bleach. However, it’s not as strong due to different chemical properties. It’s less corrosive, less damaging to fibres and more environmentally friendly. The problem with hydrogen peroxide is that it doesn’t function as a good stain remover at temperatures below 40°C.
Luckily, we use a peracetic acid derivative known as PAP. This is an even stronger bleaching agent which does perform well at low temperatures. We can remove oxidizable stains on coloured garments at temperatures below 40°C!
Stain Types: Tea, Coffee, Red Wine
Blood and other proteins are far easier to remove under alkaline conditions. Hydrofinity detergent only provides a wash pH that is slightly higher than neutral. We add alkali booster to increase the pH of the wash liquor even further. There are many different types of booster but sodium hydroxide is amongst the most common.
Hard water can be a problem in some regions of the UK. It contains metal ions that inhibit the effectiveness of detergent. This results in poor wash efficacy and greying of linen. Boosters contain sequestering agents which combine with metal ions to reduce the impact of hard water.
You may have noticed that the specific emulsifier is only good for removal of certain oils. The other key feature of using a booster is that it forms emulsions with fat-soluble oils. In adding booster to the Hydrofinity chemical suite, we have also covered a broader range of oils!
Stain Types: Vegetable Oils, Silicone Oils, Wax, Grease
Sours are acidic, hence the name. They are added to the final rinse of the wash process. They are designed to neutralise any residual alkali from the main wash that is not removed during the rinse stage.
They’re not used to target any kind of stain. You might be thinking, “is it really necessary to add more chemical if not to improve stain removal”? The answer is an emphatic yes. Alkali that remains on the cloth reacts with heat during drying to cause yellowing or galling of linen.
We use a sour called sodium bisulphite because it’s bifunctional. It serves as an antichlor as well as a sour. It counteracts any trace chlorine left on the fabric. Any remaining sodium hypochlorite would accelerate rotting of cellulose during the drying process. Our sour extends linen lifetime in the presence of bleach.
So, there you have it. Every chemical that we use has an important function, we hope you agree! The great thing about washing with XOrbs is that we don’t have to use as much so we can reduce your chemical cost whilst improving sustainability. Everyone’s a winner!
Aren’t there a few chemicals missing?
The simple answer is no.
Hydrofinity detergent contains sufficient levels of OBA (Optical Brightening Agents) so we don’t have to use a specific whitener to give whites that extra gleam!
Some foam is a good thing but too much foam hinders effective laundering. It reduces the additional mechanical action provided by the XOrbs. We don’t experience excess levels of foam because Hydrofinity detergent has low-foaming properties and we use reduced volumes. That’s why we don’t have to use a separate antifoam to suppress foaming.
Surely extra soft towels are desirable? Fabric softeners have become something of a moot point recently. Softeners contain Quaternary Ammonium Compounds or Quats which prevent static cling during drying. What’s bad about them?
✗ They’re allergens that cause skin and respiratory irritation.
✗ They’re harmful to aquatic organisms and don’t biodegrade.
✗ They’re water repellent and reduce the absorbency of towels.
Fortunately, XOrbs provide roll friction during the wash phase that lift or fluff surface fibres. This is why Hydrofinity won’t provide fabric softeners, but we will provide a soft finish!
Trust us, if there’s a chemical that will improve our process sustainably then we will consider it. At Hydrofinity, we want to offer you the highest standard of wash without putting the environment at risk.