Chemistry of Detergents and Professional Carpet Cleaning Chemicals
What chemistry is involved in carpet cleaning detergents?
The four fundamentals of soil removal are:
- Temperature
- Agitation
- Chemical action
- Time
As you decrease the use of one of the four fundamentals of soil removal, the need for using one or more of the remaining fundamentals increases.
- Temperature is especially critical when removing cooking grease and other materials with a high melting point.
- Agitation aids in lifting matted fibers, distributing pre-conditioning agents, and soil suspension.
- Chemical action is what the chemicals are designed to accomplish and what follows below. Of course, the longer the chemical has time to work on the soil, the more likely the soil will be removed.
- Time extension is one of the primary purposes of the presprays.
How does a warm water extraction cleaning detergent, such as our PCA™ Formula 5 work?
There are nine basic steps that a properly formulated detergent follows in the wet extraction carpet cleaning process:
1. Electrostatic Charge Cancellation
Have you noticed how kids like to rub balloons on their shirts and then stick them to the wall? That is due to the electrostatic charge on the balloon. In like manner, before all the soil can come off; the detergent has to cancel any electrostatic charge bonding the soil to the fibers.
2. Neutralization
Why are nearly all detergents are alkaline? Because nearly all soils and most staining agents are acidic. As a result, an alkaline cleaner performs best at removing these soils because they bring these acids into solution. In fact, ALL OTHER THINGS BEING EQUAL, the higher the pH, the better the cleaning. But, we are restricted to only moderate pH levels on carpets (below pH 10 on stain-resistant nylon carpets). pH levels above 10 have a very adverse effect on the stain-blocking mechanism in stain-resist nylon carpets and should never be used on natural fibers. Additionally, all other things being equal, the higher the pH, the more likely dyes will bleed and browning will occur.
3. Chemical Change
We can actually carry out a chemical reaction between the detergent and certain oily soils in the carpet. This chemical reaction is called SAPONIFICATION. These oils are vegetable/animal fat and oil from cooking, body oils, etc. Oils like these will react with alkali to form soap. An example of this is how soap was made in the frontier days. The mother would heat up a kettle of bear grease in a big kettle with water. The grease would just melt and float on the water because it hates water. She then added lye or wood ash, and the fat was turned into soap, which not only dissolves in water but also is a detergent! This is another reason that higher pH usually results in better cleaning.
4. Sequestration
Sequestration is a fancy chemical name meaning basically water-softening. There are four primary reasons for adding a sequestering agent to a detergent:
- Prevent clogging of the nozzle filters, etc.
- Make the detergent much more effective (water hardness reduces the effectiveness of detergents).
- Prevent the dulling effect of scum formation, just like the scum formation on your bathtub.
- Prevent resoiling due to scum formation.
However, we strongly recommend the use of a water softener in areas of extremely high water hardness to further improve cleaning and prevent scale build-up in the clean water tank.
5. Penetration
If you look at a piece of soot through a microscope, you will see that it is an uneven mass filled with air pockets not likely to dissolve in water - in fact it even floats on water. A conventional detergent “eats” away at this soil mass layer by layer. That’s fine if you’re scrubbing a tile floor, but not in the carpet cleaning business! We only have microseconds to get that dirt out!
Therefore, a properly formulated carpet wet extraction detergent has to instantly destroy this dirt particle, which is exactly what happens. The detergent molecule actually drives the water into the particle, forces the air out of the soil to fully wet out all surfaces, and explodes it apart. This action can be described as releasing CHEMICAL ENERGY.
6. Dispersion
Now the soil must be evenly dispersed (distributed evenly) throughout the solution because it wants to come back together.
7. Suspension
The soil is now removed, but it still really would much prefer going back to the carpet. Therefore, a good detergent has to contain suspending agents which keep the soil particles “suspended” in the detergent solution until the solution is pulled out of the carpet by the vacuum and air movement action.
Without this suspending action, it is quite possible to end up with a carpet looking dirtier and dingier than when you started! Why? You brought up all the “muck” from the “sewer” but it then spread out on the surface of the carpet before you got it all picked up! Additionally, the heavier grit particles fall back to the backing. Without good suspension, you will frequently have streaking, resulting in having to go back and reclean.
8. Emulsification
Emulsification is the process of removing those oils that do not saponify; i.e., they don’t react with alkali and turn into soap. These are motor oils, exhaust fumes, common pollution oils, lubricants, silicones, furniture polish, sun tan lotion, tobacco smoke residue, lubricating grease, oils from skin and pet hair, etc.
We can remove oily soils in two ways: strong solvents or emulsification.
Essentially, oil hates water (85% of the cleaning challenge). Our objective is to get oil and water married! We put a molecule into our detergent, which we call EMULON™. The Emulon molecule is composed of two parts: one part of the molecule loves oil and hates water (hydrophobic) and dissolves in oil while the other part loves water (hydrophilic) and hates oil. The oil-soluble end penetrates into the oil with the water-soluble portion sticking out into the water. Hundreds of these Emulon molecules surround this oil particle, break it into smaller particles, and pull it into the water by changing the very nature of both the water and the oil. A familiar example of an emulsion would be salad oil. If you mix vinegar and oil, you get two layers. No matter how hard you shake it or heat it, it separates into two layers! Yet, you can go to the grocery store and find all kinds of salad dressings that don’t separate! How did they do that? They added chemical emulsifiers, which results in a creamy emulsion that does not separate. Isn’t it great to know that you are eating chemicals?
9. Release
Now that we have done all these things to the soil, is it ready to go up the vacuum tube yet? NO! It still has to be physically released from the carpet by the mechanical action (mechanical energy) of the water flow.
Temperature
This would be a good place to mention thermal energy. There has been a debate between two schools of thought as to what is the best temperature for wet extraction cleaning.
One side says “the hotter the better”, because cleaning power doubles for every 18° F. increase in temperature. They say this because many chemical reactions double for every 18° F. increase in temperature, above a certain critical temperature. However, the main objective in cleaning is to be above the melting point of the soil (try cleaning butter off a knife with cold water vs. hot water).
The other side says that high temperatures are unsafe to carpet and people and unnecessary. The carpet dyes and protectors are also more readily removed at the higher temperatures.
Well, both sides are correct! ALL OTHER THINGS BEING EQUAL, cleaning improves with increased temperature on any kind of surface. However, there are surfactants and emulsifiers available today with which one can formulate a product specifically to perform at its best at a particular temperature range. By using these specialized surfactants, it is usually unnecessary to strive for the highest temperatures possible. In fact, cleaning compounds of this type will outperform at moderate temperatures the old-fashioned surfactants at high temperatures! Only in the case of extremely grease-laden carpets in restaurants is it really necessary to increase the temperature of the Bane-Clene system.
Remember also that a loss of temperature will occur from the solution tank to the carpet surface. Factors that determine the degree of temperature loss are: solution hose length, distance of the tee-jet opening from the surface of the carpet and the outside temperature (especially in the winter) with truck-mounted equipment outside.
Instead of using higher temperatures, use better chemicals!
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