Encapsulation and Crytallization

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Serious issues are continuously raised in our industry when specific encapsulation products are criticized because they do not "crystallize" in a Petri dish.

An Investigative Discussion by Bridgepoint Systems

Doyle Bloss and Tom Forsythe

Encapsulate technology is all the rage in the cleaning industry.  Its impetus for development is the result of a few important needs in the carpet cleaning industry.  Carpet manufacturers are taking more interest in the chemical composition of cleaners being used on their carpets.  Carpet manufacturers are demanding cleaning solutions which leave no soil attracting residue on carpets.  Many surfactants used in cleaning formulas have sticky residues, which attract soil if not properly extracted out of the carpet. The first step toward the development of encapsulating surfactants was adding polymers to embrittle non-ionic surfactants to reduce stickiness of the residue.  The next step was to develop surfactants with polymers, which surrounded soil and carpet fibers.  This residue surrounded both the soil and fiber making vacuuming more effective in both the short run and the long run.  The use of this type of technology made vacuums a more efficient extraction tool and increased the duration between maintenance cleanings and the effectiveness of vacuuming.

Commercial carpet cleaners are always seeking ways of increasing productivity when cleaning carpets while maintaining their profits per job.  The ability to brush in a cleaner without having to do a complete hot water extraction improves their efficiency significantly in a commercial setting, particularly when developing an on-going maintenance program.  Subsequent vacuuming following encapsulation cleaning continues the soil extraction process. Also since extraction is not done with water, the carpets dry very quickly which is a tremendous advantage in a commercial setting.

The encapsulation cleaning solution can also be improved by the inclusion of fluorochemical fiber protectors.  Most protectors will limit the ability of soil to bond to a fiber, which is what the encapsulate technology performs.  However, protectors will also provide surface tension to make liquid spills clean up easily.  Some protectors with acid dye resistors will fill up dye sites in nylon carpet to make nylon carpet harder to stain.  One part of fiber protection is accomplished in every cleaning with encapsulation, that is coating fibers to prevent the bonding of soil.

The measurement of whether a encapsulation cleaner “crystallizes” is not the only key determinant of soil protection and re-soiling prevention. First, there are many forms of crystal “lattice” structures with as many different physical and chemical attributes. Polymers vary widely in structure and chemical make up. To say that a product definitely can cause resoiling or does not encapsulate because it does not leave flakes in a Petri dish after the water evaporates out of it is an oversimplification of the process. First, true crystallization is not leaving a flaky residue. A crystal residue is just that. It looks like a crystal or a snowflake. Anionic surfactants traditionally used in shampoos will often do that.

We have dried down many versions of encapsulating cleaners on several occasions. What they could be classified as is a “brittle film-forming material”. Compare a diamond, (a true crystal), to a super hard shiny coating on a dish. The brittle coating might fracture into small pieces but it is essentially a weak brittle film.  A crystal would be characterized as having a distinct geometric shape or shapes, like salt or sugar. (Right angles, rhomboids, multi-faceted complex shapes, etc.) A film can be brittle or soft, but would generally not have a distinct geometric shape. How things dry-down and form crystal structures is widely varied. The very crystal structure itself may form before all of the liquid phase has had time to “dry’ out, entrapping liquid inside the crystal structure or beneath the top layer of the film. The polymer or surfactant might separate from the formula, depending on solubilities, before the water is completely gone leaving the surfactant and polymer disassociated in the dish. The polymer might be brittle but separate from the tacky surfactant.

Following is a series of photos recently took that shows the result of a dry-down of three different encapsulation formulations. Two of them are commercially available and one is an experimental formula. Note the middle sample is clearer. It is nearly 100% Acrylic polymer.  In the photographs below, three cleaning formulations claiming to “encapsulate” soil were poured into aluminum soil weighing pans and dried at 100 degrees Celsius to remove all volatiles and water. As you can see, each of these formulations has a unique appearance in this state. None of the samples below would be classified as a true “crystal.” All of the samples below however, could be classified as brittle, film-forming materials. One of these products claims to “dry down to a crystal.” This is fundamentally not the case. The re-soil prevention protection provided by all three of these formulas is good. However, only two of these formulations provide soil and stain protection, while one provides only soil protection. All 3 of these respective formulas provided a range of adequate to superior cleaning efficacy. Thus the principle that “crystallization” in a Petri dish is the best way to determine the effectiveness of an encapsulating cleaner does not hold up to scientific measurement.

Second, the real value of a Petri dish demonstration will reveal whether the residue left behind is sticky or tacky and holds onto or "binds" the soil. There are many structures of polymer chemistry that will not bind soil that do not dry to a "crystallized" structure. Crystallization is not the only measure. For example, some fluorochemical carpet protectors would not “crystallize”, yet they do not cause resoiling. The opposite is true. They are soil resistant agents. Some of the encapsulation carpet cleaners contain fluorochemicals or fluorosurfactants to help resist soiling.

Professional cleaners should be keenly aware that the best way to effectively test the effectiveness of an encapsulating cleaner is to use it in the field. To systematically dismiss a product from consideration for use because it does not "crystallize" in a glass jar or in a Petri dish does not fully take into consideration the full structure of the chemistry of encapsulation cleaning.

There is no doubt that a product that crystallizes or “embrittles” can be a good encapsulate. However, many of the encapsulating products that claim to “crystallize,” do not actually form a true crystal. Keep in mind also, there are other technologies, both proprietary and readily available, that do make excellent encapsulation products. Bridgepoint Systems manufactures two leading formulas for encapsulation cleaning – Encapuclean and Encapuclean with Maxim. Both have distinct application advantages. Both have been demonstrated and tested not to contribute to rapid carpet resoiling.

Encapsulation cleaning can open new doors in commercial carpet cleaning for professional carpet cleaners. Effective cleaning rates from 150 to 300 square metres per hour with extremely quick drying times (10 to 60 minutes) provide the professional with the ability to competitively bid against all carpet cleaning systems or methods on the market. Some encapsulation formulas (e.g., Bridgepoint Encapuclean)  contain fluorochemical additives that provide a higher level of soil resistant technology to keep the carpet looking cleaner longer, while improving the performance of subsequent vacuuming and spot removal They may also contain higher levels of fluorochemicals along with acid dye resistors (e.g., Bridgepoint Encapuclean with Maxim) which enhance the stain resistant effectiveness of many commercial carpets. Carpet re-soiling prevention reduces cleaning frequency demands and satisfies carpet manufacturer warranties. Encapsulation cleaning can be used with almost every type of agitation system (rotary shampoo brush, bonnet pad, counter-rotating cylindrical brush, orbital and oscillating) allowing the professional to take advantage of equipment already owned. Bridgepoint Encapuclean and Encapuclean with Maxim may be effectively used with all of these types of agitation systems. With the use of counter-rotating brush agitation, the professional can achieve bonnet cleaning rates of productivity, while avoiding rotary agitation action when it is discouraged by the carpet manufacturer. There is a reason why there is so much discussion surrounding encapsulation cleaning. Understanding how it works and where to apply it is the first step in adding new business for the professional.

Accelerated Soil Drum Test

The following photos demonstrate the relative soiling performance of the listed materials when compared in an ASTM 6540 accelerated soil drum test. The results indicate that the Encapuclean with Maxim product, by far, offers the highest level of soil protection of the materials tested. The competitive "crystallizing" material, while better than control, was not nearly as effective at preventing soiling in this study. All materials were applied per label instructions at equal amounts by weight.


                                                                                 WITH MAXIM