Sustainable Use of Preservatives in Wet Cleaning ... - Schülke & Mayr

Sustainable Use of Preservatives inWet Cleaning WipesModern preservative systems must balance marketing andproduction demands to create eco–friendly products.By Wolfgang Siegert,Technical Support Manager InternationalSchülke & Mayr GmbHSpecial Additives InternationalConsumers have come to expect certain key attributesfrom wet cleaning wipes relative to their intendeduse, such as soil removal capacity, anti-static properties,streak-free shine, etc. Additionally, environmentalacceptability, including the sustainable use of raw materials,is becoming a decisive factor for many customers.The synergistic combination of benzisothiazolinone(BIT), methylisothiazolinone (MIT) and bis(3-aminopropyl)dodecylamine(BDA) has been shown to minimizethe level of biocidal actives needed for preservation. Withthis new sustainable “full-life” protection concept, it ispossible to control waterborne contaminations andmicrobially polluted natural nonwovens by adding a single,optimized dosage of preservative. Along with the economicand product safety improvements, this approachfulfills the demand for eco-labels, like European Flowerand the White Swan, as well as the stringent requirementsof the German Öko Test magazine.The Goal of ‘Green’ ProductsSustainability is being systematically integrated intomany companies’ principles and business processes.Often, the use of biocides is an essential point of discussion.Despite some consumer concerns about theuse of biocides, the use of these materials has enableda shift toward products with greater biodegradability. Ina sense, the value of biocides to the quality of our livesis beyond price. Their function is preventative, primarily,minimizing waste of natural and limited resources whilereducing exposure to harmful microorganisms.The wish to produce “green” products should notresult in insufficiently preserved, unsafe products.Proliferation of pathogenic microorganisms, productspoilage and visible growth of mold on the wet wipes arethe risk of inadequately protected products.Microorganisms live in all parts of the biosphere wherethere is liquid water; they are critical to nutrient recyclingin ecosystems as they act as decomposers. Populationsof microorganisms undergo exponential growth. Figure 1demonstrates the growth of Escherichia coli at optimalconditions with a generation time of 20 minutes.Wet tissues are an excellent medium for the growthof bacteria, yeast and mold. The wet tissue liquids aremostly aqueous; the cellulose is a good nutrient; thenonwoven is always moderately contaminated withmicroorganisms; and the storage temperature is nearlyFigure 1Exponential growth of microorganisms in water (generation time 20min).optimal for microbial growth. Environmental requirements(e.g., from the EU Detergent Directive) to use onlybiodegradable detergents increase the susceptibility ofwet tissues to microbial infection. The demand for flushablewipes and the increased use of natural fibers makemold growth, with its easily visible staining, more likely.To ensure consumer safety and product stability, theaddition of preservatives to wet wipes is necessary.Preservatives should protect the product by preventingbiological degradation for a certain period. However, atthe end of the lifecycle of a wet wipe (the disposal) thebiocide should be biodegradable.Biocidal properties and biodegradability are not in26 HOUSEHOLD &PERSONAL CARE WIPES/FALL 2012

conflict. For example, a concentration of ethanolbetween 50% and 90% is a good disinfectant. It actsbetween 13% and 50% as preservative. Below 13%ethanol will be degraded biologically to acetic acid.Conflict & BalanceFrom a marketing perspective, preservation should beas “green” as possible. Some consumers would preferpreservative-free.From the view of plant management, preservationshould control any microbial contamination during production.This would save costs for cleaning and sanitizing.ISO 22716 (Cosmetics—Good ManufacturingPractices (GMP)—Guidelines on Good ManufacturingPractices) gives guidelines for the production, control,storage and shipment of cosmetic wipes. While manufacturingin a simpler production line, ignoring hygienicdesign, may be acceptable for hard surface cleaningwipes, it is advisable to follow the same GMP rules forthe manufacture of cosmetic wipes to minimize potentialmicrobial contamination.The target for product development is to select a preservativesystem balancing marketing and productiondemands to achieve an eco–friendly, sustainable product.Contamination SourcesMicrobial contamination of wet wipes can occur duringtheir manufacture. The majority of the contaminants arepresent in the source of water and in the raw materials,including the nonwoven as well as in equipment andplumbing lines (tanks and pipes). Certain microorganismsproduce biofilms that can adhere to the surfaces ofplumbing systems containing water, to processing tanksand to other environments in the factory. These biofilmsare in general resistant to treatment with biocides.The incoming water in factory pipe systems can originatefrom various sources. Each source supplies a different,usually specific composition of organic and inorganicconstituents of chemical ingredients in the water.Additionally, the hardness of the water can play animportant role. Possible water sources include:• Town water from a single public well• Town water from various public wells• Water from (river) shore filtrates• Water from (sea) shore filtrates• Water from reservoirs• Water from a privately owned source• Water from a privately owned wellIon exchangers are often sources of contamination. Theion exchanger resins can be colonized by biofilms, which areunharmed even after regeneration with sodium hydroxideFigure 2Optimized dosage concept for a fast-acting in-can preservative.solution or hydrochloric acid. An exchanger plant fed withdrinking water (organism count

ial challenge testing (schülke FeuTukoTest) using thispreservative combination.Labels & LegislationThe European Ecolabel is a voluntary scheme establishedin 1992 to encourage businesses to market eco-friendlyproducts and services. Products and services awardedthe Ecolabel carry the flower logo, allowing consumers,both public and private—to identify them easily.Established product groups include all-purpose cleanersand cleaners for sanitary facilities;detergents for dishwashing machines;hand dishwashing detergents; laundrydetergents and soaps, shampoos andhair conditioners.The ecological criteria required toreceive the EU Ecolabel for all-purposecleaners and sanitary cleaners are publishedin the Commission Decision2011/383/EU.The formulation shown in Figure 3would fulfill the demands of thisCommission Decision. Additionally, thepackaging criteria for these productsmust be taken into account. Accordingto the European Chemicals Agency(ECHA) “Guidance on requirements forsubstances in articles,” a wet cleaningwipe is a combination of an article(functioning as a container or a carriermaterial) and a substance or mixture.For such ready-to-use products, theweight utility ratio (WUR) of the primarypackaging must be below 150 gramspackaging per liter of cleaning solution.For example, with a 120 grams persquare-meter spunlace three-layer structure(67% viscose, 33% PET, sawatexTriLace), a maximum water absorptioncapacity of approximately 1,000% is possible8 . In practice, it was found that theactual absorption capacity was 830%.This allows for the application of 1,000grams of cleaning solution on 120 gramsof nonwoven, so there is still some spacefor a soft pack. Production of an Ecolabelconformingwet wipe product is possible.In Summary…A limited number of biocidal activesare available for the preservation ofhousehold wet cleaning wipes. Manyactives are under public discussionand harsh actives may lead to negativereviews in test magazines. Newconcepts in preservation are required.28 HOUSEHOLD &PERSONAL CARE WIPES/FALL 2012

Minimizing the use of preservativesis essential according to the philosophy“as little as possible, but asmuch as technically necessary.”The utilization of boosting effectsof actives helps to reduce use concentrations.An optimized dosageconcept improves and helps toensure product safety, even with lowuse concentrations of in-can preservatives.Optimized preservativeapplication, combined with specialnonwoven qualities, allow productsto fulfill EU Ecolabel criteria. HPCWAbout the author: Wolfgang Siegertis technical support manager withSchülke & Mayr GmbH. He can bereached at +49 40 52100 528;wolfgang.siegert@schuelke.com;www.schuelke.com.Figure 3All-purpose wet wipe that passes microbial challenge test.there’s only so much land to meet the needs of our ever-expandingpopulation. luckily, cotton is a crop that provides both fiber and foodsimultaneously. cottonseed oil is used in the commercial food industry.whole cottonseed is fed to dairy cows, and in the future, it could feed other livestockand even people. so, when you choose to put cotton in your nonwovens, it’s not achoice between fiber or food. cotton provides both. visit cottoninc.com/nonwovensto find out more about your cotton nonwoven options.AMERICA’S COTTON PRODUCERS AND IMPORTERS. Service Marks/Trademarks of Cotton Incorporated. © 2012 Cotton Incorporated.HOUSEHOLD &PERSONAL CARE WIPES/FALL 2012 29