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, Cleaning products play an essential role in our dailylives. By safely and effectively removing soils, germsand other contaminants, they help us to stay healthy,

I care for our homes and possessions, and make ourì surroundings more pleasant.

The Soap and Detergent Association (SDA)recognizes that public understanding of the safetyand benefits of cleaning products is critical to theirproper use. So we've revised Soaþs and Detergentsto feature the most current information in aneasy-to-read format. This second edition summarizeskey developments in the history of cleaning products;the science of how they work; the proceduresused to evaluate their safety for people and theenvironment; the functions of various productsand their ingredients; and the most commonmanufacturing processes.

SDA hopes that consumers, educators, students,media, government officials, businesses and othersñnd Soaps and Detergents avaluable resource ofinformation about cleaning products.

¡: 2nd Edition

li¡: orpq¿ The Soap ancl Detergent Association

COIUTEIUTS

HISTORY .........4

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HISTORYI The origins of personal cleanlinessI date back to prehistoric times. Since

water is essential for life, the eadiestpeople lived near water and knewsomething about its cleansing 11 Records show that ancient

rr Egyptians bathed regularly. TheEbers Papyrus, a medical document

r The earlv Greeks bathed forÐ aesthetié reasons and apparentlydid not use soap. Instead, theycleaned their bodies with blocks ofclay, sand, pumice and ashes, thenanointed themselves with oil, andscraped off the oil and dirt with ametal instrument known as a strigil.They also used oil with ashes.

Clothes were washed without soapin streams.

properties - at least thatit rinsed mud offtheir hands.

the excavation of ancientBabylon is evidence thatsoapmaking was knownas early as 2800 B.C.Inscriptions on thecylinders say thatfats were boiledwith ashes, whichis a method ofmaking soap, butdo not refer to thepurpose of the "soap."Such materials werelater used as hairstyling aids.

from about 1500 8.C.,describes combininganimal and vegetableoils with alkaline saltsto form a soap-likematerial used fortreating skin diseases,as well as for washing

¿r As Roman civilization advanced, soI AiA bathing. The first of rhe famous

Roman baths, supplied with water fromtheir aqueducts, was built about 3l2B.C.The baths were luxurious, and bathingbecame very popular. By the secondcentury 4,D., the Greek physician, Galen,recommended soap for both medicinaland cleansing purposes.

e 467 A.D. and the resulting

9 A soap-like material found<t in clay cylinders during ¡ Soap sot its name. acc(

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Roman legend,

decline in bathing habits, muchof Europe felt the impact of fìlthupon public health. This lack ofpersonal cleanliness and relatedunsanitary living conditionscontributed heavily to the greatplagues of the Middle Ages, andespecially to the Black Death ofthe l4th century. It wasn't untilthe lTth century that cleanlinessand bathing started to come backinto fashion in much of Europe.

Still there were areas of themedieval wodd where personalcleanliness remained important.Daily bathing was a commoncustom inJapan during the MiddleAges. And in lceland, poolswarmed with water from hotsprings were popular gatheringplaces on Saturday evenings.

¡ At about the sameÍl time, Moses gave

the Israelites detailedlaws governing personalcleanliness. He alsorelated cleanliness tohealth and religiouspurification. Biblicalaccounts suggest thatthe Israelites knew thatmixing ashes and oilprodtrced a kind ofhair gel.

Sapo, where animals wereRain washed a mixture of meltedfat, or tallow, and wood ashes downthe clay soil along the Tiber River.Women found that this clay mixturemade their wash cleaner with muchless effort.

The ancient Germans and Gaulsare also credited with discovering a

substance called soap, made of goat'stallow and ashes, that they used

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O Soapmaking was an established:, craft in Europe by the seventhcentury. Soapmaker guilds guardedtheir trade secrets closely.Vegetable and animal oils wereused with ashes of plants, alongwith fragrance. Gradually morevarieties of soap became availablefor shaving and shampooing, aswell as bathing and laundering.

r0..*13:n:l;ffffii:ffi1ii.to their ready supply of raw materials suchas oil from olive trees. The English beganmaking soap during the l2th century. Thesoap business was so good that in 1622,KingJames I granted a monopoly to asoapmaker for $100,000 ayear. Well intothe 19th century, soap v/as heavily taxedas a luxury item in several countries.When the high tax was removed, soapbecame available to ordinary people, andcleanliness standards improved.

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1 1 Commercial soapmaking in ther r American colonies began in 1608

with the arrival of several soapmakers onthe second ship from England to reachJamestown, VA. However, for manyyears, soapmaking stayed essentially ahousehold chore. Eventually, professionalsoapmakers began regularly collectingwaste fats from households, in exchangefor some soap.

lO A maior step toward large-scalerá commercial soapmaking occurredin l79l when a French chemist,Nicholas Leblanc, patented a process formaking soda ash, or sodium carbonate,from common salt. Soda ash is the alkaliobtained from ashes that combineswith fat to form soap.The Leblanc processyielded quantitiesof good quality,inexpensivesoda ash.

lÁ, N9" important to ther r advancement oI soaptechnology was the mid-1800sinvention by the Belgianchemist, Ernest Solvay, of theammonia process, which alsoused common table salt, orsodium chloride, to make sodaash. Solvay's process furtherreduced the cost of obtainingthis alkali, and increased both

the quality ând quantityof the soda ash

available formanufacturingsoap.

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French chemist,of the chemical

and fatty acids.His studiesestablished thebasis for both fat andsoap chemistry.f

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t> The science of modernIJ ,o^p-rking was born some

20 years later with the discovery bY

Michel Eugene Chevreul, another

with the development ofpower to operate factories,made soapmaking one ofAmerica's fastest-growingindustries by 1850. At thesame time, its broadavailability changed soap

from a luxury item to aneveryday necessity. rl(/ith

this widespread use camethe development of mildersoaps for bathing and soaps

for use in the washingmachines that were availableto consumers by the turn ofthe century.

16 ffi i":iï,,i iåii10.,,.",.',the same t¡ntil 1916, when the firstsynthetic detergent was developed inGermany in response to a WoddrJlar I-related shortage of fats formaking soap. Known today simply asdetergents, synthetic detergents arenon-soap washing and cleaningproducts that are "synthesized" or puttogether chemically from a variety ofraw materials. The discovery ofdetergents was also driven by the needfor a cleaning agent that, unlike soap,wot¡ld not combine with the mineralsalts in water to form an insolt¡blest¡bstance known as soap curd.

18The first detergents were usedchiefly for hand dishwashing

and fìne fabric lat¡ndering. Thebreakthrough in the developmentof detergents for all-purpose laundryuses came in 1946, when the fìrst"built" detergent (containing asurfactant/builder combination) wasintroduced in the U.S. The surfactantis a detergent product's basiccleaning ingredient, while thebuilder helps the surfactanr towork more efficiently. Phosphatecompounds used as bt¡ilders inthese detergents vastly improved

performance,making them

.ì--- st¡itable forcleaning heavily

' soiled laundry.

By 1953, sales of detergents inthis country had surpassed

Since those early achievements in detergent and builder chemistry,new product activity has continued to focus on developingcleaning products that are efficient and easy to use, as well as safe

for consumers and for the environment. Here's a summary of someof those innovations.

I 950sAutomatic dishwasher powders

1960sPrewash soil and stain removersIaundry powders with enzymesEnzyme presoaks

1970sLiquid hand soapsFabric softeners (sheets and wash-cycle added)Multifunctional products (e.g., detergent with

fabric softener)

t9B0sDetergents for cooler water washingAutomatic dishwasher liquidsConcentrated laundry powders

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.¡ 7 Household detergent producrionr r in the United States began in the

early 1930s, but did not really take offuntil after Vorld War IL The war-timeinterruption of fat and oil supplies aswell as the military's need for a cleaningagent that would work in mineral-richsea water and in cold water had ft¡rtherstimulat€d research on detergents.

1990sUltra (superconcentrated) powder and liquidUltra fabric softenersAutomatic dishwasher gelsLaundry and cleaning product refìlls

detergents

19those ofsoap. Now detergents haveall but replaced soap-based productsfor laundering, dishwashing andhousehold cleaning. Detergents(alone or in combination with soap)are also found in many of the barsand liquids used for personalcleansing.

To understand what is needed to achieve effective cleaning, it is helpful to havea basic knowledge of soap and detergent chemistry.

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SURFACE TENSION

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SURFACTANT

St¡rfactants perform other importantft.¡nctions in cleaning, such as loosening,emulsifying (dispersing in warer) andholding soil in suspension until it can berinsed away. Surfactants can alsoprovide alkalinity, which is useful inremoving acidic soils.

Water, the liquid commonly used for cleaning, has aproperty called surface tension. In the body of thewater, each molecule is surrounded and attracted byother water molecules. However, at the surface,these molecules are surrounded by other watermolecules only on the water side. A tension is createdas the water mol€cules at the surface are pulled intothe body of the water. This tension causes water tobead up on surfaces (glass, fabric), which slowswetting of the surface and inhibits the cleaningprocess. You can see surface tension at work byplacing a drop of water onto a countertop. The dropwill hold its shape and will not spread.

In the cleaning process, surface tension must bereduced so v/ater can spread and wet surfaces.Chemicals that do this effectively are called surfaceactive agents, or surfactants. They are said to makewater "wetter."

Surfactants are classifìed bytheir ionic (electrical charge)properties in water: anionic(negative charge), nonionic(no charge), cationic (positivecharge) and amphoteric (eitherpositiv€ or negative charge).

In a triglyceride molecule, threefatty acid molecules are attachedto one molecule of glycerine.There are many types oftriglycerides; each type consistsof its own particularcombination of fatty acids.

a carboxylic acid groupconsisting of one hydrogen (H)atom, two oxygen (O) atoms,and one carbon (C)atom; plus

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a hydrocarbon chain attached to thecarboxylic acid group. Generally, it ismade up of a long, straight chain ofcarbon (C) atoms each carryingtwo hydrogen (H) atoms.

ANTON|C (NEGAT|VE)

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Soap is an anionic surfactant. Other anionic as v¡ell as nonionic surfactants arethe main ingredients in today's detergents. Now let's look closer at thechemistry of surfactants.

SOAPSSoaps are water-soluble sodium or potassium salts of fatty acids. Soaps aremade from fats and oils, or their fatty acids, by treating them chemically with a

strong alkali.First, let's examine the composition of fats, oils and alkalis; then we'll review

the soapmaking process.

Fats and OilsThe fats and oils used in soapmaking come from animal or plant sources. Eachfat or oil is made up of a distinctive mixture of several different triglycerides.

Fatty acids are the components of fats and oils that are used in making soap.They are weak acids composed of two parts:

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HYDROCARBONCHAIN

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AlkaliAn alkali is a solt¡ble salt of an alkali metal like s<lclium or potassium. Originally,the alkalis usecl in soapmaking wcre obtained from thc ashcs of plants, but thcyarc now made commcrcially. 'I'oclay, the tcrm alkali describcs a sr¡bstancc thatchemically is a base (the op¡>osite of an acid) ancl that reacts with andneutralizes an acid.'I'hc common alkalis t¡secl in soa¡rmakingare s<¡dit¡m hydroxide (NaOH), also callcdcaustic soda; and potassium hydroxiclc(KOH), also called caustic potash.

NaOH KOH

How Soaps Are Made

Saponifìcation of fats and oils is the most widely used soapmakingprocess. This method involves heating fats and oils ancl reacting them with a

liquid alkali to produce soap and water (neat soap) pltrs glycerine .

'l'he carboxylate encl of thcsoa¡r molect¡le is attractcclto water. It is callecl thchyclrophilic (water-lovirrg)end.'I'hc hydrocarbonchain is attractcd to oil andgrease and rcpcllecl bywater. It is known as thchyclrophobic (water-hating)end.

How Water Hardness Affects Cleaning Action

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The fary acids are then purified by distillationand neutralized with an alkali to prodtrce soapand watcr (neat soap).

Although soap is a good clcaning agent,its effectiveness is reduced when usedin hard watcr. Harclness in water iscat¡sed by the presence <¡f mineral salts

- mostly those of calcitrm (Ca) anclmagnesium (Mg), but sometimes alsoiron (Fe) and manganese (Mn). Themineral salts react with soap to form aninsoluble precipitate known as soap filmor scr¡m.

Soap film does not rinse away easily. Ittends to remain behind and producesvisible clcposits on clothing and makesfabrics fcel stiff. It also attaches to theinsides of bathtubs, sinks and washingmachines.

Some soa¡r is rrsed up by reacting withhard water minerals to form the film.This reduces thc amount of soapavailablc for cleaning. Even whenclothes are washed in soft water, somehardness minerals are introdt¡ced by thesoil on clothes. Soap molecr¡les are notvery versatile and cannot be adapted totoday's variety of fibers, washingtemperatur€s and water conditions.

Ttre other maior soapmaking process is the neutralization of fatty acidswith an alkali.

Fats ancl oils archydrolyzed (split) withhigh-pressure steam toyield cnrcle fatty acids anclglycerine.

FATTY ACID ALKALI SOAP WATER(NEAT SOAP)

lùl¿hen the alkali is sodit¡m hyclroxiclc, a sodit¡m soap is formed. Soclium soaps are"hard" soaps. Bar soaps are harcl soaps. Whcn the alkali is potassium hyclroxidc,a potassium soap is formed. Potassium soaps are softer and are fotrncl in someliquid hand soaps and shaving creams.

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SURFACTAIUTS IIU DETERGEIIIÎS

A detergent is an effective cleaning product because it contains one or moresurfactants. Becat¡se of their chemical makeup, the surfactants used in detergentscan be engineered to perform well under a variety of conditions. Suchsurfactants are less sensitive than soap to the hardness minerals in water andmost will not form a fìlm.

Detergent surfactants were developed in response to a shortage of animal andvegetable fats and oils during rVodd War I and Vodd lVar II. In addition, a

substance that was resistant to hard water was needed to make cleaning moreeffective. At that time, petroleum was found to be a plentiftll source for themanufacture of these surfactants. Today, detergent sr¡rfactants are made from avariety of petrochemicals (derived from petroleum) and/or oleochemicals(derived from fats and oils).

Let's discr¡ss the main components of detergent surfactants.

Petrochemicals and OleochemicalcLike the fatty acids used in soapmaking, bothpetroleum and fats and oils contain hydrocarbonchains that are repelled by water but attracted to oiland grease in soils. These hydrocarbon chain sourcesare used to make the water-hating end of thesurfactant molecule.

Other ChemicalsChemicals, such as sulfur trioxidc, sulfuric acid andethylene oxide, are used to produce the water-lovingend of the surfactant molecule.

AlkalisAs in soapmaking, an alkali is used to make detergentsr¡rfactants. Sodium and potassium hydroxide are themost common alkalis.

How Detergent SuÉactants Are Made

Nonionic SurfactantsNonionic surfactant molecules are produced by first converting the hydrocarbonto an alcohol and then reacting the fatty alcohol with ethylene oxide.

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These nonionic surfactants can be reacted further with sulfur-containing acidsto form another type of anionic surfactant.

HOI,U SOAPS AIUD DETERGEIUTS t,vORK

Three types ofenergy are needed for good cleaning results:

o chemical energy, provided by the soap or detergent;o thermal energy, provided by warm or hot water; ando mechanical €nergy, provided by a machine or hands.

These rypes of energy interact and should be in proper balance. Irt's look athow they work together.

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Let's assume we haveoily, greasy soil onclothing. rùØater alonewill not remove this soil.One important reason isthat oil and greasepresent in soil repel thewater molecules.

Now let's add soap ordetergent. The surfactant'swater-hating end isrepelled by water butattracted to the oilin the soil. At the sametime, the water-loving endis attracted to the watermolecules.

NONtONICSURFACTAIÛI

These opposing forcesloosen the soil andsuspend it in the water.Warm or hot water helpsdissolve grease and oil insoil. Washing machineagitation or hand rubbinghelps pull the soil free.

Anionic SurfactantsThe chemical reacts with hydrocarbonsderived from petroleum or fats and oilsto produce new acids similar to fatty acids.

A second reaction adds an alkali to the newacids to produce one type of anionicsurfactant molecule.

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INGREDIENTSSoaps and detergents are essential to personal ancl public health. Through theirability to loosen and remove soil from a surface, they contribute to goodpersonal hygiene; redt¡ce thc presence of germs that cause infectiot¡s cliseases;extend the useñ¡l life of clothes, tableware , linens, surfaces ancl furnishings; anclmake our homes and workplaces mor€ pleasant.

soaps and detergents found in thc home can be grouped into four generalcategories: personal cleansing, laundry, dishwashing ancl household cleaning.within each category are different product types formulated with ingredientssclected to perform a broad clcaning ft¡nction as well as to cleliver propertiesspecifìc to that product. I(nowing the different products and their ingredientshelps you select the right prodr.rct for the cleaning job.

PRODUCTS

Personal Cleansing Productsinclt¡de bar soaps, gels, liquid soapsand heavy duty hand cleaners. Theseproducts get th€ir cleaning actionfrom soap, other surfactants or acombination of the two. The choiceof cleaning agent helps determine theproduct's lathering characteristics,feel on the skin and rinsability.

Laundry Detergents and Laundry Aidsare available as liquids, powders, gels, sticks,sprays, pumps, sheets and bars. They areformulated to meet a variery of soil ancl stainremoval, bleaching, fabric softening andconditioning, and disinfectant needs undervarying water, temperature and use conditions.

Laundry detergents are either Boosters enhance the soil ancl staingeneral purpose or light duty. General removal, brightening, buffering andpurpose detergents are suitable for all water softening performance ofwashable fabrics. Liquids work best on detergents. They are used in the washoily soils and for pretreating soils and in addition to the detergent.stains. Powders are especially effective n-.in rifting out cray

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Light duty detergents are used for ãimcult stains and soils. \ifhen addedhand or machine washing lightly to ttr. *ash water, they increasesoiled items and delicate fabrics. cleaning power.

Bar soaps or Gels are formr¡latedfor cleaning the hands, face and body.Depending on the other ingredients,they may also moisturize the skinancl/ or inhibit odor-causing bacteria.Specialty bars inclucle transparent/translucent soaps, lnxury soaps andmedicated soaps.

Liquid soaps are generallyformt¡lated for cleaning hands, andfeature skin conditioners. Somecontain antimicrobial agents that killor inhibit disease-causing bacteria.

Heavy duty hand cleaners areavailable as bars, liquids, powders andpastes. Formulated for removingstubborn, greasy dirt, they mayinclude an abrasive.

Laundry aids contribute to theeffectiveness of laundry detergentsand provide special functions.

Bleacbes (cblorine ønd otygen)whiten and brighten fabrics and helpremove stubbom stains. They convertsoils into colorless, soluble particlesthat can be removed by detergents andcarried away in the wash water. Liquidchlorine bleach (usually a sodiumhypochlorite solution) can also disinfectand deodorize fabrics. Oxygen (color-safe) bleach is more gentle and workssafely on almost all washable fabrics.

Bluings contain a blue dye or pigmenttaken up by fabrics in the wash orrinse. Bluing absorbs the yellow partof the light spectnlm, count€ractingthe natt¡ral yellowing of many fabrics.

Føbríc softeners, added to the fìnalrinse or dryer, make fabrics softer andfluffier; decrease static cling, wrinklingand drying time; impart a pleasingfragrance and make ironing easier.

Preutasb soil and stain remouers areused to pretreat heavily soiled andstained garments, especially thosemade from synthetic fìbers.

Starcbes, fabric finisbes and sízings,used in the fìnal rinse or after drying,give body to fabrics, make them moresoil-resistant and make ironing easier.

Water softeners, added to the wash orrinse, inactivate hard water minerals.Since detergents are more effective insoft water, these proclucts increasecleaning power.

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Hand dishwashing detergentsr€move food soils, hold soil insuspension and provide long-lastingsuds that indicate how much cleaningpower is left in the wash water.

Automatic dishwasher detelgents,in addition to removing food soils andholding them in suspension, tie uphardness minerals, emulsiff grease

and oil, suppr€ss foam caused byprotein soil and help water sheet offdish surfaces. They produce little orno suds that wot¡ld interfere with thewashing action of the machine.

Rinse agents are t¡sed in addition tothe automatic dishwasher detergent tolower surface tension, thus improvingdraining of the water from dishes andt¡tensils. Better draining minimizesspotting ancl fìlming and enhancesdrying.

Dishwashing Productsinclude detergents for hand andmachine dishwashing as well as

some specialty products. Theyare available as liquids, gels,powders and solids.

Film removern remove build-up ofhard water fìlm and cloudiness fromdishes and the interior of thedishwasher. They are used instead ofan ar¡tomatic dishwasher detergent ina separat€ cycle or together with thedetergent.

Lime and rust removers removedeposits of lime and/or rust from theinterior of the dishwasher. They areused when no dishes or otherdishwasher products are present.

All-pur¡lose cleaners penetrate andloosen soil, soften water and preventsoil from redepositing on the cleanedsurface. Some also disinfect.

Abrasive cleansers remove heavyaccumulations of soil often found insmall areas. The abrasive action isprovided by small mineral or metalparticles, fìne steel wool, copper ornylon particles. Some also disinfect.

Specialty cleaners are designed forthe soil conditions found on specifìcsurfaces, such as glass, tile, metal,ovens, carpets and upholstery, toiletbowls and in drains.

Gløss cleaners loosen and dissolve oilysoils found on glass, and dry quicklywithout streaking.

Glass and. multì-surface cleanersremove soils from a variety of smoothsurfaces. They shine surfaces withoutstreaking.

Tub, tíle and sink cleaners removenormal soils found on bathroomsurfaces as well as hard water deposits,soap scum, rust stains, and/or mildewand mold. Some also treat surfaces toretard soiling; some also disinfect.

Household Cleaners are available as liquids,gels, powders, solids, sheets and pads for use onpainted, plastic, metal, porcelain, glass and othersurfaces, and on washable floor coverings.Because no single product can provide optimumperformance on all surfaces and soils, a broadrange of products has been formulated to cleaneffìciently and easily. \ùflhile all-purpose cleanersare intended for more general use, others workbest under highly specialized conditions.

Metal cleanels remove soils and polishmetalware. Tarnish, the oxidation ofmetal, is the principal soil found onmetalware. Some products alsoprotect cleaned metalware againstrapid retarnishing.

Ouen cleaners remove burned-ongrease and other food soils from ovenwalls. These cleaners are thick so theproduct will cling to vertical ovensurfaces.

Rug sbampoos and uplJolstery cleanersdissolve oily and greasy soils and holdthem in suspension for removal. Somealso treat surfaces to repel soil.

Toilet boul cleaners prevent or removestains caused by hard water and rustdeposits, and maintain a clean andpleasant-smelling bowl. Some productsalso disinfect.

Drain openers unclog kitchen andbathroom drains. They work byproducing heat to melt fats, breakingthem down into simpler substancesthat can be rinsed away, or byoxidizing hair and other materials.Some use bacteria to prevent grease

build-up which leads to drain clogging.

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IIUGREDIEilTS

surfactants and builders are the major components of cleaning products. otheringredients are added to provide avariety of functions, such as increasingcleaning performance for specifìc soils/surfaces, ensuring product stability andsupplying a unique identity to a product. Let's examine how surfacrants andbuilders work and then review other commonly used ingredients.

Sudactants

Surfactants, also called surface active agents, are organicchemicals that change the properties of water (see pagel0). By lowering the surface tension of water, surfactantsenable the cleaning solution to wet a surface (e.g., clothes,dishes, countertops) more quickly, so soil can be readily

loosened and removed (usually withthe aid of mechanical action).Surfactants also emulsify oily soilsand keep them dispersed andsuspended so they do not settle backon the surface. To accomplish theirintended jobs effectively, many cleaning productsinclude two or more surfactants.

Emulsify, disperse,suspend soils

surfactants are generally classified by their ionic (electrical charge)properties in water.

Anionlc surfactants are t¡sed in laundryand hand dishwashing detergents;household cleaners; and personalcleansing products. They ionize (areconverted to electrically chargedparticles) in solution, carry a negativecharge, have excellent cleaningproperties and generally are highsudsing. Linear alþlbenzene sulfonate,alcohol ethoxysulfates, alþl sulfatesand soap are the most common anionicsurfactants.

Nonionlc surfactants are low sudsing and are typicallyused in laundry and automatic dishwasher detergentsand rinse aids. Because they do not ionize in solutionand thus have no electrical charge, they are resistant towater hardness and clean well on most soils. The mostwidely used are alcohol ethoxylates.

Cationic surfactants are used in fabric softeners andin fabric-softening laundry detergents. Other cationicsare the disinfecting/sanitizing ingredient in somehousehold cleaners. They ionize in solution and have apositive charge. Quaternary ammonium compounds arethe principal cationics.

Ampboteric surfactants are used in personal cleansingand household cleaning products for their mildness,sudsing and stability. They have the ability to be anionic(negatively charged), cationic (positively charged) ornonionic (no charge) in solution, depending on the pH(acidity or alkalinity) of the water. Imidazolines andbetaines are the major amphoterics.

Builders

Builders enhance or maintainthe cleaning effìciency of thesurfactant. The primaryfunction of builders is toreduce water hardness.This is done either bysequestration or cbelation@olding hardness minerals insolution), by precipitation(forming an insolublesubstance), orby ionexcbange (trading electrically charged particles). Complex phosphates andsodit¡m citrate are common sequestering builders. Sodium carbonate andsodit¡m silicate are precipitating builders. Sodium aluminosilicate (zeolite) is an

ion exchange builder.Builders can also supply and

maintain alkalinity, which assists

cleaning, especially of acid soils;help keep removed soil fromredepositing during washing;and emulsify oily and greasysoils.

Lower surfacetens¡on

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lngredient KeyThe following key indicates the product category in wlrich an ingreclientmay be used. The key letters appear below each ingredient.

@ o @Personal Cleansing Laundry Dishwashing Household Cleaners

lngredient Prirnary Functions Typical Examples

Abrasives

@@Strpply smoothing, scrubbing ancl/<>rpolishing action

CalciteFeldsparQuartzSand

Aclds Net¡tralize or adjust alkalinity of otheringredients

Àcetic acidCitric acidHydrochloric acidPhosphoric acidSulfuric acid

Alkalis@o@

o Neutralize or adjust acidity of otheringredients

o Make surfactants and builders moreeffìcient

o Increase alkalinity

Ammoniumhydroxide

EthanolaminesSodium carbonateSodium hydroxideSodium silicate

Antimicrobialagents

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Kill or inhibit growth of microorganismsthat cause diseases and/or oclor

Pine oilQuatemary ammonium

compoundsSodium hypocNoriteTriclocarbanTriclosan

Antirede¡lositionagcilts

o@Prevent soil from resettling after removalduring washing

Carboxymethylcellulose

PolycarborylatesPolyethylene glycolSodium silicate

Bleacheso@

Help whiten, brighten and remove stains

chk¡rine bleaclt Sodium hypochlorite

orygen bleacb Sodium perborateSoclium percarbonate

Colorants@o@

o Provicle special identity to producto Provide bluing action

Pigments or dyes

Corosioninhibitors

o@Protect metal machine parts and finishes,china patterns ancl metal utensils

Sodium silicate

)t

Ingredient Primary Functions Tyrpical Examples

Dnzymes

o@o Proteins classifìed by the type of soil they

break down to simpler forms for removal bydetergent

. Cellulase reduces pilling and greying of fabricscontaining cotton and helps removeparticulate soils

Amylase (starch soils)Lipase (fatty and oily

soils)Protease (protein soils)Cellulase

Fabric sotfiteningagents

oImpan softness ând control static electricity infabrics

Quatemary ammoniumcompowrds

Fluorescentwhiteningagents

o

Attach to fabrics to create a whitening orbrightening effect when exposed to daylight

Colorless fluorescingcompounds

Fragrances

@o@. Mask base odor of ingredients and package. Cover odors of soilo Provide special identity to producto Provide pleasant odor to clothes and rooms

Fragrance blends

Hydrotropes

o@o Prevent liquid products from separating

into layersr Ensu¡e product homogeneity

Cumene sulfonatesEthyl alcoholToluene sulfonatesXylene sulfonates

Opacifiero

@o@. Reduce transparency or make product opaquer Provide a special effect

PolymersTitanium dioxide

Preservativec

@o@Protect against natural effects of product aging,e.g., decay, discoloration, oxidation andbacterial attack

Butylatedhydrox¡oluene

Ethylene diaminetetrâacetic acid

Glutaraldehyde

Proceosing aids

@o@o Provide important physical characteristics,

e.9., proper pour or flow, viscosity, solubility,stability and uniform density

o Assist in manufacttrring

ClaysPolymersSodium silicateSodium sulfateSolvents

Solvents

o@o Prevent separation or deterioration of

ingredients in liquid productso Dissolve organic soilsr Clean without leaving residue

EthanolIsopropanolPropylene glycol

Suds controlagento

Ensure optimum sudsing (foaming) level needed for a cleaning job

suds stabllizers

@Maintain high sudsing where suds level is animportant indicator of cleaning power

AlkanolamidesAlþlamine oxides

suds suppressors

o@Control sudsing where suds would interferewith cleaning action

Alþl phosphatesSiliconesSoap

23

As consumer neecls ancl lifcstylcs change, and as new mant¡facturing processesbecome available, the soa¡t and detergent industry responds with new products.A commitment to safefy is a top priorify from the time a company begins workingon a new product and continues as long as the product is in the marketplace.Companies cvalt¡ate thc safety of existing cleaning products by talking withconsrìmers, reviewing scientific developmcnts ancl monitoring prodtrct use datathat may affcct the safety assessment proccss.

To determine thc safety of a cleaning procluct ingredient, inclustry scientistsevalt¡ate the toxicity of the ingredient. Toxicity is generally definecl as anyharmft¡l effect of a chemical on a living organism, i.e., a human, an animal, aplant or a microorganism. Since all chemicals, including water (H2O), are toxict¡nder certain conclitions of exþosure, scientists mt¡st considcr a number offactors affecting exposure. These include the duration and frequency of exposureto the ingre(lient; the concentration of the ingredient at the time of exposure;and the route and manner in which the exposure occurs, c.g., eye, skin oringesti<rn. This information is essential whether assessing tht. eÍfect on humans,animals, plants or microorganisms.

Ilecause human safety and environmental evaluations consider different typesof exposures, they are evaluated by clifferent procedures. The principal steps inthe assessment process are, howevcr, the same . They involve:

f assembling cxisting clata on toxicity ancl exposlrre;

2 ctetermining where new information is nee<Jecl ancl, if neccssary,carrying out appropriate studies; and

3 determining whether preclictecl exposure levels are bclow levelsthat cat¡se significant toxic effects.

This safety cvalt¡ation proccss enables scientists to predict the potential risk,if any, associated with the usc of tlre ingredient or product, ancl det€rmine if it issafe f<¡r consumers and the environment.

Medical science has long confirmed the importantrelationship between cleanliness ancl health. Theregular r¡sc of cleaning products is ft¡ndamental to thehealth of ot¡r society and the well-being of its people.

Ilecause cleaningproducts are part of our

everyday lives, it is essential that they notpresent a significant risk to health. Inconsidering the human safety of anindividual ingredient or product,toxicologists (scientists who assess thesafety of a chemical) are concerned withthe effects from two types of exposures:intended and uninten<Ied. Intended.exposures occur with use of a cleaningprodr.rct according to the manufacturer'sdirections. Unintended exposures can resultfrom misuse, through improper storage or byaccidental contact, sr.¡ch as when a liquiddetergent is splashed in the eye.

Hazards from these types of exposures are

evaluated from information obtained throughacute (short-term) and chronic (long-term)tests and through a review of existing data.Expected exposure routes are considerecl as

part of this evalt¡ation.Human safety evaluations begin with the specific ingredients and then move

on to the whole product. The effects for all ingredients are considered as theproduct is formulated.

Toxicologists compare the expected exposure to the expected effect duringboth prodtrct manufacture and use. How will workers be exposed in the plant?

\ùøhat is the intended use of theproduct? Is it to be diluted?Undilt¡ted? Used daily in thehome? Weekly in the workplace?Toxicologists also consider theexpected effect of an unìntendedexposure. What is the potentialbaz.ard, for example , if a childdrinks a product directly fromthe bottle?

IIIITE¡UDED

[;'*;gÏ

UNIIIITEIUDED

24 25

If this human safety evaluation indicates an unacceptable risk, it may bepossible to make the risk smaller by changing the manufacturing process;reformulating to reduce or eliminate an ingredient contributing to the toxiceffect; or using labeling or a child-resistant closure. If the risk cannot be reduced,the product will not be marketed.

Even though manufacturersformulate cleaning products toensure that they are safe or havevery low risk, human health effectscan stiil result from unintendedexposure. To warn consumersabout a specific hazard, householdcleaning products carry cautionarylabeling whenever necessary. Forconsumers, this is one of the mostimportant features of the label.

Federal regulations govern how precautionary statements related to humansafety are used on household cleaning product labels. The regulations requirethat statements follow a standard format. There is first a "signal word," followedby a short description of the potentialhazard. The following chart shows thesignal words - CAUTION or WARNING and DANGER - and what rhey mean:

POISON, which rarely appears on household cleaning products, is the strongestindication of hazard and means that accidental exposure cot¡ld cause severemedical effects. The term may be found on household lye and on some car careproducts, such as antifreeze.

Along with the safety evaluation process and cautionary labeling, an extensiveconsumer education program on the proper use, storage and disposal of cleaningproducts supports the human safety efforts of the soap and detergent industry.In addition, the industry works closely with poison control cent€rs to assurethat, shot¡ld an accidental exposure occur, treatment information is available tohealth care providers. Together, these activities enable consumers to usecleaning products with confìdence in both their safety and performance.

Most household cleaning products are formulated to beused with water and "go down the drain" into wastewatertreatment systems(municipal sewagetreatment plants orseptic tank systems).

To assure that products are safe for theenvironment, manufacturers evaluate theimpacts of product ingredients in wastewatertreatment systems, streams, rivers, lakes and Vestuaries Scientiff¡- nrincinlec thqt qte u¡idetrr i SÊl¡ÙÄó¡estuaries. Scientifìc principles that are widely i SÊliiÄä¡

' ,

¡cr¡oøira¡t lrrr tfra ¡ø¡t:a2¡at ^âA -Áã,.t^t^-, I rnelru¡¡¡r ]recognized by the technical and regutatory i,-,,:;iÄff*j.r{;scommunities are used to assess the risk tothe environment of these impacts.

Environmental risk assessmentconsiders the exposure concentrations andeffects of individual ingredients. Two setsof information are used in theseassessments. One set enables industryscientists to predict the concentration of theingredient from all sources, including cleaning products, at various locations inthe environment (the predicted Øcþosure concentratíon). The other set is usedto find the highest concentration of the ingredient at which no harmwill occur to animals, plants or microorganisms living in the environment(the noeffect concentratlon). comparing the predicted exposure concentrationand the no'effect concentration enables scientists to determine whether the useof an ingredient is saþ for tbe enulrontnent. The planned use of a cleaningproduct ingredient is acceptable if the predicted exposure concentration islower than the concentration that would harm animals, plants or microorganisms.

&dË

I' s-EPTtCTANK

SYSTEM

PREDICTED EXPOSURECONCENTRATION

NO-EFFECTCONCENTRATION

SAFE FORENVIRONMENT

26 27

This information applies to ingredientsprocessed through household septic tanksystems as well as municipal treatment plants.Two basic steps occur in the treatment ofwastewater in both systems. The fìrst step,called primary treatment, consists ofthe removal of solidmaterial, such as

grit or grease,from the

wastev/ater by pbysical means, i.e., settling andflotation in tanks. The second step, calledsecondary treatment, removes the dissolvedmaterial by btological means, i.e., consumptionby microorganisms.

It is in the secondary treatment stage where themost important process in reducing the exposure concentration of

detergent ingredients occurs. This is called biodegradatlon.Biodegradation describes how organic (carbon-

containing) detergent ingredients, likesurfactants, enzymes and, fragrances, arebroken down into carbon dioxide, waterand minerals by the action of micro-organisms such as bacteria. ,A,t this stage,biodegradation reduces the amount of

detergent ingredients discharged into theenvironment to levels that do not present a

risk to fìsh or other aquatic life. Any smallamounts of chemicals which are not biodegraded or removed duringse¡ñ/age treatment are diluted in surface vr'aters, soil and theocean. They continue to biodegrade or be rernovedfrom water by attaching to solids, a processknown as adsorptlon.

Some inorganic (not carbon-containing)detergent ingredients, such as phosphates,zeolites and some dyes, also attach to solids,and are further treated during processing of thebiosolids (sludge) procluced in primary andsecondary treatment. Biosolids are often used as

fertilizers and soil conditioners.Because of modern treatment methods, only an insignificant amount of the

ingredients used to clean clothes, dishes, home and workplace surfaces actuallyreaches the environment. And that amount is at such levels as to not cause anyadverse effects.

lmproving Eny¡ronmentel Ouality

The soap and detergent industry is committecl to understanding the impact of itsproducts and packages on the environment. with this understancling comes theability to reduce their impact and improve their environmental quality.

Manufacturers of cleaning products have been leaders in reducing packagingwaste and encouraging sound waste disposal practices. Aclvances in technologyhave resulted in products that are more concentrated, products that combine twofunctions in one, products with refill packages and packages that use recycledmaterials. concentrated products need less energy to manufacture and transport,and require less packaging. Multiftlnctional products eliminate the need forseparate packages. Refìll packages allow consumers to reuse primary packagesmany times, decreasing the amount of packaging used and the volume of trashgen€rated. Plastic and paperboarcl that woulcl otherwise be thrown away becomeusable materials through recycling.

Through education and community programs, the soap and cletergent industryhelps consumers learn how to reduce waste and how best to dispose of it.consumers are reminded that the environmentally wise way of handling any

household cleaning product is to buy onlythe amount that can be used; to use it all upor give it away; and, if it must be disposecl, todispose of it propedy. As a rule of thumb,products designed for use with water shouldbe disposed of by pouring down the drain;solid products such as scouring pads shouldbe ptrt into the trash.

A promising method under development forimproving the environmental quality of aproduct is life cycle assessment (LCA). LCAdescribes a "cradle-to-grave" look at all theenvironmental impacts of a product andits package, from acquiring raw materialsthrough manufacture and distributionto consumer use and disposal. One 1

advantage of LCA is that it can determinewhether reducing an environmentalimpact in one area, such as manufacturing,shifts the impact to another, such asdisposal. LCA also helps to identify whereenvironmental improvement efforts shouldbe focused.

Sound scienti.fìc information provicles the fotmdation for the soap and detergentindustry's cofirmitment to safety. The industry maintains this commitment withoutcompromising product performance, convenience or cost-effectiveness.

PHYSICAL

BIODEGRADATION

ADSORPTION

BIOLOGICAL

2A 29

¡ '-")-,1/ ..'-¿- ,

f.i- |

¡--

oils and neutralization of fatty acids,were described in the Chemistrychapter (see page 12).

Soap was made by the batch kettleboiling method until shortly afterWorlcl War II, when continuousprocesses were developed.Continuot¡s processes are preferredtoday because of their flexibility,speed and economics.

Both continuot¡s and batch processesproduce soap in liquid form, calledneat soap, and a valuable by-product,glycerine. @ The glycerine isrecoverecl by chemical treatment,followed by evaporation and refining.Refined glycerine is an importantindustrial mat€rial used in foods,cosmetics, drugs and many otherproducts.

The next processing step aftersaponification or neutralization isclrying. Vact¡um spray drying is used toconvert the neat soap into dry soappellets.Ø The moisture content of thepellets will vary depending on thedesired properties of the soap bar.

In the final processing step, the drysoap pellets pass through a bar soap

fìnishing line. The firsr unit in the lineis a mixer, called an amalgamator, inwhich the soap pellets are blendecltogether with fragrance, colorants andall other ingredients. O Themixture is then homogenized andrefìned throrlgh rolling mills andrefìning plodders ro achieve thoroughblending and a uniform texture.Finally, the mixture is continuouslyextruded from the plodder, cut intobar-size t¡nits and stamped into its fìnalshape in a soap press. €)

Some of today's bar soaps are called"combo bars," because they get theircleansing action from a combinationofsoap and synthetic surfactants.Others, called "syndet bars," featuresr¡rfactants as the main cleansingingredients. The processing methodsfor manufacturing the synthetic basematerials for these bars are verydifferent from those t¡sed in traditionalsoapmaking. However, with someminor modifications, the finishing lineequipment is the same.

Soap ancl detergent mant¡factr¡ring consists of a broad range of processing andpackaging operations. The size and complexiry of these operations vary fromsmall plants employing a few people to those with several hr¡ndred workers.Prodr¡cts range from large-volume types like launclry detergents that are t¡sed ona regular basis to lower-voh¡me specialties for less frcquent cleaning needs.

Cleaning products come in three principal forms: bars, powders andliquicls. Some li<¡r.ricl products are so viscot¡s that they are gels. The first step inmanufacturing all threc forms is the selection of raw materials. Raw materials are

chosen accorcling to many criteria, inchtding their human anct environmentalsafety, cost, compatibiliry with other ingreclients, ancl the form and performancecharacteristics of the fìnishecl procluct. While actual production processes mayvary from mantrfacturer to manufacturer, there are steps which are common toall proctucts of a similar form.

Let's start by looking at bar soap manufacturing and then we'll review theprocesses used to make powder and liquid detergents.

Traditional barsoaps are madefrom fats and oilsor their fätty acicls

which are reactedwith inorganicwater-solublebases. The mainsources of fats arebeef ancl muttontallow, while palm,coconut and palmkernel oils are theprincipal oils t¡secl

in soapmaking.The raw materials may be pretreatedto remove impurities and to achievethe color, odor and performancefeatures desired in the finished bar.

'Ihe chemical processes for makingsoap, i.e ., saponification of fats and

rilìrr#r----------IIt-rlr{llrlr¡ ..- , iI'L.'IIri¡llr¡lì¡ll¡ì!i 'ii-* li r"*ørt-i¡ lrr ...1 I ...i ¿r.,á' I

itr'-, rlIewcentHer$L-----------

3r

B'IR SOAPS

IE

30

POWDER DETERGEIUTS LIQU¡D DETERGEIUTS

Powder dctergents are prodtrced byspray drying, agglomeration, drymixing or combinations of thesemethods.

ln the spray drylng process, dryand liquid ingredients are fìrstcombine<J into a slurry, or thicksuspension, in a tank called a

crutcher. O The slurry is heatect anclthen pr.rmped to the top of a towerwlrere it is sprayed through nozzlesunder high pressure to produce smalldroplets. The droplets fall through acurrent of hot air, forming hollowgranules as rhey dty.Ø The drieclgranules are collected from thebottom of the spray tower where they

are screened to achieve a relativelyuniform size. @

After the granules have beencooled, heat sensitive ingredients thatare not compatible with the spraydrying temperatures (such as bleach,enzymes and fragrance) are added. @Traditional spray drying producesrelatively low density powders.

New technology has enabled thesoap and detergent industry to reducethe air inside the granules during spraydrying to achieve higher densities. Thehigher density powders can be packedin much smaller packages than wereneeded previously.

Both batch and continuous blendlngprocesses are used to manufactureliquid and gel cleaning producrs.Stabilizers may be added duringmanufacturing to ensure theuniformity and stability of thefïnished product.

In a typical continuous process, dryand liquid ingredients are added andblended to a r¡niform mixture usinginline or static mixers.

Recently, more concentrated liquidproducts have been introduced. Onemethod of producing these productsuses new high-energy mixingprocesses in combination withstabilizing agents.

The final step in the manufacture of soaps anddetergents is packaging. Bar soaps areeither wrapped or cartoned in singlepacks or multipacks. Detergents,including householdcleaners, are packagedin cartons, bottles,pouches, bags or cans.The selection ofpackaging materialsand containers involvesconsiderations ofproduct compatibiliryand stability, cost,package safety, solidwaste impact, shelfappeal and ease ofuse.

UQUIDINGREDIENTS

DRYINGREUEÜIS

I

uQutD , r DRYINGREDIÊNTS 1 INGREDIEMfS

uQurDINGREDIEMÍS

SPRAY DRYING

Agglomeratioz, which leads tohigher density powders, consists ofblending dry raw materials wirh liquidingredients. Helped by the presence ofa liquid binder, rolling or shear mixingcauses the ingredients to collide andadhere to each other, forming largerparticles.

Dry rnlxíng or dry blending isused to blend dry râw materials.Small quantities of liquids may alsobe added.

AGGLOMERATION

uQliDINGREDIE¡ITS

DRY

INGREDIENIS

r..-r.:+F.r--€'-.1I Jt*'r. II r" Ii DETEnGEilT I,- - i l--,.'.-t---'

DRY MIXING

BIENDING PROCESS

PACKAGIIUGI

3233

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