ICS Magazine

The Low-Moisture Carpet Cleaning Revolution

March 1, 2007


Low-moisture carpet-cleaning technologies are changing so rapidly that it has become difficult to keep up with all the new developments. The chemistry and equipment are evolving at an increasingly faster rate, creating incredible expectations and anticipation for what the future might bring.

Since much of this technology is relatively new, the greatest need is to increase the level of knowledge across the entire industry, from the chemical and equipment manufacturers to the carpet mills and professional cleaners (the Low Moisture Carpet Cleaners Association published a White Paper in 2006 defining the basics of low-moisture cleaning to lay the groundwork for assisting professionals in decisions regarding low-moisture carpet cleaning methods and the optimum environments for their use.).

In a nutshell, the term “low-moisture carpet cleaning” refers to methods and/or procedures that allow carpet fibers to dry to their natural state in two hours or less. The key to low-moisture carpet cleaning is to reduce the freestanding moisture in the carpet, enhancing the carpet’s ability to dry very evenly and very quickly, eliminating large spots created by pooled moisture and other problems associated with excess moisture.

Essentially, low-moisture carpet cleaning generally describes methods that clean with water at levels below the saturation point of the fabric. When the fiber has reached its saturation point, it cannot absorb more water. All additional water becomes freestanding water, and can puddle on the backing or travel down beyond the backing onto the subflooring and even into the subflooring.

Every carpet exists in a unique environment, with variations in construction, installation, substrates, traffic, soil levels, soil types, temperature, humidity and location. With this in mind, we should assume one system is never optimal in all environments, yet all systems can excel when used by a trained, skilled operator in the appropriate setting. Proper training and complete understanding of the cleaning processes and procedures is critically important. Let’s face it: without proper training and knowledge, all carpet cleaning systems will fail.

Fueling this movement are the new carpet-cleaning chemicals available today. These new encapsulation chemistries have re-ignited interest in methods that were long questioned because they were known to leave residues contributing to re-soiling. These new chemistries actually use the residues as part of the cleaning process; they rely on the equipment for the agitation, while the new chemicals help cause the soils to dry to a particulate that allows them to be removed through vacuuming. In order to get a better understanding of how low-moisture carpet cleaning systems work, we need to start by understanding how the chemicals work.

The first chemistries used on early carpets were merely soaps, not very different from what you might have used to wash your face or hair. Because of the absorption of solution into the fiber, there was always a case of chemical residue. In the early days, carpet-cleaning chemicals were absolutely known re-soil quickly.

Next, manufacturers added a compound known as Ludox, a wax-like substance thought to fill the grooves and crags in natural fibers to prevent soil from being caught. It was an improvement; however, it certainly did not solve the re-soiling problem. In fact, it brought on a host of other problems related to the dirty slurry created during the cleaning process, which was ultimately caught in the drying process. It caused the carpets to loose their ability to refract light properly and the carpets would tend to “ugly out” after repeated cleanings.

In the ’50s and ’60s we went through the phase of detergent “encapsulation.” The chemicals would separate the dirt from the fiber, encapsulate the soil, and either be allowed to dry out and then vacuumed, absorbed into an absorbent media or be flushed out with extractors. This was an improvement over the old soaps, and it did mark the start of reducing re-soiling, but it didn’t eliminate the problem.

In the mid ’80s, chemists again sought to improve the situation of re-soiling. The early solvents and surfactants were liquids in their raw state, and as a result did not fully dry down beyond a gelatin or tacky residue. The thought at the time was to add a component that would force the chemical to dry down to a hard crystalline material. Ultimately, it was thought that acrylic co-polymers (similar to floor finish) could be added, causing the residues to dry to a hard acrylic shell around the fiber and the soil. This hard shell would fracture under foot traffic and the action of the beater bar of a vacuum cleaner, breaking away from the fiber and falling toward the backing where it could be vacuumed away at a later date. It was this technology that created terms like “acrylic co-polymer embrittlement agents” and “crystallizing detergents.” The concept became very popular, ultimately receiving praise and accolades like “true encapsulation cleaning.”

The potential negative aspect of the use of acrylics revolves around the dirty slurry that is created during the cleaning process. Obviously, some of this residue gets left behind in the fiber, and the problem is that it is no longer clear, clean acrylic-laced detergent. It would become more of an amber brown acrylic crystal created from mixing with soil during the cleaning process. The obvious danger of this approach is that some of the acrylic “shell” can be left on the fiber. Then, the bigger problem becomes one of trying to “strip out” the residual acrylics without using strippers, which would be deleterious to the carpet.

In the ’90s fluorocarbon chemistry was introduced to carpet-cleaning chemicals; it has been referred to as “second-generation encapsulation chemistry.” The concept was to leave a Teflon-like substance behind on the fiber, causing dirt and soil to slide off the fiber, like a fried egg slides off a frying pan. The concept had great promise, but again there were some potential pitfalls. Also, the government had some concerns surrounding the long-term health effects of fluorocarbons, a debate that still rages.

On a more relevant note, many were found to be hygroscopic, meaning that they attracted moisture from the atmosphere (dampening the carpet in humid conditions), which in itself could easily contribute to re-soiling. It is important to note, however, that it’s not correct to state categorically that fluorochemicals cause re-soiling; it depends a great deal on the quality and the quantity of the fluorocarbons being used in the formulation.

Now, in the last few years, we have seen some brand new chemistries evolving. These new chemistries – let’s call them third-generation encapsulation chemistries – have rewritten many of the old rules. The most intriguing concept is that many of them use entirely new solvents and surfactants that actually dry down, along with the soils, into a powder on their own, without the need for other additives like acrylic co-polymer embrittlement agents. They are later vacuumed out as a dry soil. These new chemicals literally strip all the soil and old residue off the carpet fiber, leaving the fiber residue-free, much like the carpet fiber was when it was new, and we all know how easy it is to vacuum soil out of new carpeting. This is often referred to as “dehydration phase cleaning,” meaning the cleaning process continues as the residues dry.

This means improvements can be achieved with its use in all carpet-cleaning methods, including hot-water extraction; rotary bonnet systems; foam shampooing; powder extraction; oscillating bonnet systems; cylindrical bonnet systems; counter-rotating cylindrical brush machines; and spot and stain removal operations, as well as sanitizer rinsing. In almost every case, the machines are used to agitate the solution in the carpet so the encapsulation process can capture the soil for removal at a later date through vacuuming. In one case, cylindrical bonnets are actually extraction-cleaned during their rotation.

In every case, the carpets appear very clean after the operation, even though some of the soil is still in the carpet. The soil left in the carpet dehydrates into a powder at the sub-surface level, unseen by the naked eye. It is through thorough vacuuming that it is completely removed.

There are many top-notch carpet-cleaning chemicals on the market today, available from a multitude of manufacturers. Unfortunately, the amount of junk on the market seriously outweighs the amount of good stuff. It is difficult and expensive to build a high-quality encapsulation product. Designing good encapsulation chemistry requires extensive R&D and sophisticated manufacturing processes, and so the cost is higher. The reality is, high-quality encapsulation products sell for $20 to $30 per gallon, sometimes more. This is in part due to the use of high-quality ingredients that will not interfere with the encapsulation process; overloading a chemical with cheap perfume oils and improper blending of low-grade fluorocarbon technology will definitely interfere with the encapsulation process (Note: This is not to be confused with the use of trace amounts of high-quality, purpose-specific fragrance oils and the proper use of high-grade fluorocarbon technology which may not interfere with the encapsulation process at all.).

The disturbing thing is that we have all seen encapsulation claims on products being sold for as little as $5 per gallon. There are numerous products out there that dry very slowly (and some that may never fully dry); products that use silicones; products that use lousy fluorocarbon technology; products blended improperly; products that separate; products that are highly discolored and cause discoloring on the carpet, etc.

Professional using carpet-cleaning chemistries may want to do some “bench chemistry,” testing on their own to make decisions about products. Don’t just take anyone’s word on it when you can actually do the tests yourself and form your own opinions. The results may truly surprise you.

The use of low-moisture carpet cleaning systems can increase the performance and appearance of the carpet, extend its useful life, enhance the ability to service carpet and minimize the downtime. Any way you look at it, it is a tool that should be considered by all professional carpet cleaners.