'The Limits of Greatness for a Traditional Fiber in the Modern WorldBy Maria C. Thiry, Features Editor

One of the oldest fibers to be made into fabrics,, wool has a long history and rich tradi-tions, "Wool has been with us for a long time. There are 25.000 years of known historyof this fiber," says Crisan Popescu. of the German Wool Research Institute (DWl an derRWTH), For much of that history, people have been wearing gamients and using textileproducts made of wool.

Wool is a fabulous fiber, say all the experts. Wool fabrics boast a soft hand, ex-cellent drape and crease recovery, odor absorption, breathability, natural flame resis-tance, natural antibacterial properties, excellent breathability. and take dye readily.The fiber has naturally built-in elasticity due to coiled proteins, according to DavidLewis of the University of Leeds, and "can absorb its own weight in moisture with-

out feeling wet.""The outdoor industry is in love with wool as a natural substitute for

V synthetics." notes Jim Heiden of Teko Socks. Wool can keep wearers cool on^ a hot day and warm on a cool day. and retains its warmth even when it is

wet. "Wool's remarkable properties for resiliency, warmth with comfort,the ability to control the microenvironment of the wearer, and more,

_ including unique aesthetic appeal, will be perennially appreciatedby the consumer," says Jeanette Cardamone of the U,S. Depart-

ment of Agriculture (USDA).With all its wonderful features as a fiber, why isn't

wool more popular? According to Popescu, the amountof wool consumed globally today is about the same

as it was in the 1950s and l')60s, "Thedemand for wool is constant, but

wool is only about 2.5% ofall the fibers in the

textile market,"

says Popescu, So., what'swrong with wool?

For all its uniqueness andwonderful properties, in manyways wool is a fiber of limits.Advances made in the woolsector of the textile industryoften involve a struggle toovercome those limits.

WHAT'S WRONGWITH WOOL?

Limited ProductionOne of the limits imposed onwool is a natural limit becausewool is a natural fiber, "Sheepproduce five to six kilos ofwool per year," notes Popescu"To produce this wool, thesheep have to be fed. Twosheep require about one hect-are for pasture. Thus the needfor pasturage limits the amount ^^^mmof wool that can be produced.If you wished to replace all the otherfibers currently being produced withwool, you would need about 100 millionsquare kilometers of good pasturage forall the sheep. So there is a natural limit onhow much wool fiber you can produce."

Even if there was a sudden miracu-lous increase in land available for pastur-age, there's no guarantee it would beused to increase wool production. "Landis valuable," notes Klaus Hannemann ofCiba Specialty Chemicals. "There iscompetition for acreage. Often, moreprofitable things can be done with theland, and the sheep farmers are compet-ing for it."

Moreover, even if the sheep fannersown sufficient acreage, it might not beprofitable to produce the wool anyway."Farmers aren't making enough moneyto grow wool right now," notes Heiden,"We need fair pricing. We need to payfanners enough to both run their farmsand enable them to innovate so that theycan produce a better fiber."

PriceIn part because of the limited production,wool is an expensive fiber. "Wool coststhree to five times as much as otherfibers," notes Hannemann, Lewis agreesthat the limits of wool are an economicproblem, not a technological one. "The

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industry just can't produce enough,cheaply enough."

Allan De Boos of Australian WoolInnovation (AWI) agrees that "Wool isan expensive raw material compared tosynthetic fibers and cotton. It is alsomore expensive to process. The coststend to keep it out of very price sensi-tive markets."

MISPERCEPTIONSOne of the limitations of wool involvesconsumer perceptions. "Many countriesdon't take wool seriously as a fiber,"notes Popescu. "There is a strong rela-tionship between consumed wool perperson and a country's gross domesticproduct (GDP), The GDP for the highestwool importing countries is at least$5,000/person. The United States is a'cotton country' and uses less wool thanis typical for their GDP. but other devel-oped countries like Japan and the UnitedKingdom are more typical in their woolconsumption."

Additionally, "Wool is a very tradi-tional fiber and has an old-fashionedimage," notes Hannemann, "Woo! coatsare being replaced by lighter weightsynthetics. Formal clothes have beenreplaced by casual wear. The prevalenceof central indoor heating has meant thatthere is no need for heavy sweaters. The

20

trend is also towards lighter weightfabrics, which means that less wool isused in the fabrics."

Consumers also worry about caringfor wool garments and are concernedthat they will felt or shrink in the wash.However, today gamients are availablein both 100% wool and wool blendsthat are machine washable. TheWoolmark brand certifies machinewashable and tumble dryable garmentsas "Total Easy Care."

"One myth needs to be dispelled."says De Boos. "Wool is not scratchy.That's not modem wool. Only woolcontaining a significant amount of fiberscoarser than 30 microns is scratchy nextto the skin. Fine wool has a luxurioussof̂ hand. Consumer perceptions ofwool being scratchy were brought on bythe use of coarse grade fibers that aren'tsuitable for garments."

"Fineness is ail important." Lewisagrees, "Fabrics made from fibers lessthan 21 microns can be wom next to theskin and are superbly soft."

Processing IssuesModem wool processing is focused ondealing with wool's tendency to felt,shrink, and pill, and with taking advan-tage of wool's dyeability.

Since wool is a natural fiber, it must

OCTOBER 2005

be scoured prior to further processing.Besides various detritus from the pasture,sheep's wool has lanolin, which has to beremoved during the scouring, accordingto Lewis. The efTIuent from wool scour-ing can be very polluting.

In the 1960s, CSIRO's Division ofTextile Industry, now Textile and FibreTechnology, developed the Chlorine-Hereosett shrinkproofing process toprevent wool from felting and shrinkingduring machine washing.' The chlorineused in the Hercosett process also leadsto hazardous effluent, which is banned inmany countries.

According to Hannemann,afterchrome dyes are often used to dyewool, especially for navy and blackshades (25-30% of the woo! marketshare), The dichromate used in this pro-cess is not only regarded as a potentialhealth hazard during processing, but alsoleaves chromium in the effluent - theamount of chromium is restricted by

many countries. According to Lewis,dyeing wool above the boil also damagesthe fibers themselves.

FINDING SOLUTIONS

SustainabilitySince wool is a natural fiber, and a re-newable resource, it's not a big stretch tosee it join the movement towardssustainability, "Wool is a clean greenfiber," says De Boos.

Heiden uses sustainably farmed woolto make his company's products. "Holis-tic sustainable wool farming is certainlypossible," he says. "The big issue withwool in how it is raised is proper grazingand farm management. We get our woolfrom a holistically sustainable sheepfann in Tasmania. They are working toreturn the native grasses to their land andthey rotate the sheep so that no sheep ison the same portion of land tor morethan half a day."

Environmentally FriendlierProducing wool in an ecological way isjust one step. Finding solutions to manyof wool's processing issues means fmd-ing ways to make wool processing moreenvironmentally friendly. "There is apromising market in the sustainable woolprocessing sector," says WilliamSchollian of American NaturalBioSolvents (ANBS),

"The market demands shrinkproof,easy care wool," says Popescu. "But thecurrently used Hercosett treatment to geteasy care wool uses chlorine, which isenvironmentally harmful." According toBrian Francois of Cognis, the use of theoxidative chlorine treatment weakens thewool fibers as well.

His company's environmentallyfriendly Securlana treatment allows woolfabric to pass Woolmark's Total EasyCare standard with only 0,5-1% shrink-age even after 40 machine wash andtumble dry cycles. "Unlike other systems

hree toTTve timesas much as other

... theindustry just can't

roduce enough^cheaply

\ enougn.OCTOBER 2DO5 V\AAAA/. AATCC, ORG

that coat the wool with polyurethane orsilicone films, ours doesn't change theaesthetics or the hand of the fabric."Francois notes. "In addition, our treat-ment improves the pilling characteristicsof wool fabrics."

The USDA has also developed a moreenvironmentally friendly process forshrinkproofing wool,"we have a domes-tic process for controlling the shrinkageof wool in machine washing invented bythe USDA ARS Eastern Regional Re-search Center, whereby a novel activatedperoxide system bleaches wool to a highlevel of whiteness at 35C for 30 minutesand is followed by enzyme treatment at45C tor 40 minutes."-

Schollian says ANBS" environmen-tally friendly shrinkproofing processdoesn't contribute to wastewater issues.His company also has a bio-based dyeingauxiliary that "reduces the traditionaldyeing time of wool by 50%, and givesnearly 100% exhaustion of the dye ontothe wool wilh outstanding crocking andwashfastness. Our low temperature pro-cess cuts processing time and costs and

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saves energy aswell. It improveshand, strengthensthe fibers, andimproves feltingresistance." saysSchollian.

According toHannemann, Cibahas an alternativeto environmentallyunfriendlyafterchrome dye-ing. "The LanasoiCE metal-free reactive dye range has thesame high fastness as the chrome dyes,but gives a softer hand and betterspinnability. The old process needs twosteps, but Ciba's Lanasoi CE range re-quires only a one step process, givingdyers higher productivity."

EnzymesEnzymes have been considered as a moreenvironmentally friendly answer to bothshrinkproofing and dyeing processes.According to Julie Clemmons of

Novozymes,"We're trying toimprove traditionalprocessing condi-tions and addressenvironmental andsafety issues byproviding an enzy-matic process toreplace some ofthe chemical con-ditions of woolprocessing."The outer surface

of wool has micro-scopic scales,which arc thecause of wool'sfelting, shrinking,and itchy proper-ties. Forshrinkprootlng,enzymes calledproteases can beused to blunt theedges of the wool'sscales. "As with allchemical treat-ments, the lengthof time andamount of enzyme

22AATCC REVIEW

used must be controlled," saysClemmons. "If the enzyme is overdosedor over processed, it can attack the liberitself and degrade strength. We are ex-perimenting on using alcohol solvents toblock the enzyme from penetrating intothe fiber and keep the action localized onthe surface scale to overcome strengthloss issues."

In the scouring process. Upases can beused to hydrolyze fats and oils. "Thisenzyme is very specific, and doesn'tdamage the fiber itself," says Clemmons.

As for enzymatic dyeing, "Undermild conditions an oxidoreductase canbe used in combination with organiccompounds to simultaneously fonn thedye and dye the wool fibers." saysClemmons. "This enzymatic process canobtain good depth of shade and fastnessproperties."

MachineryAccording to Popescu, plasma technol-ogy has shown promise as an environ-mentally friendly and non-chemical wayof shrinkproofing wool fabrics. However,it may be some time before the technol-ogy is adopted for routine production useby textile mills. Besides the high initialinvestment costs involved in any newtechnology, "the textile industry is veryconservative in adopting new technology,and wool is the most traditional segmentof the textile industry," says Popescu.

THE FUTURE OF WOOLWhat's next for wool? "Plenty of thingsare next," asserts Popescu. "But remem-ber that after 25,000 years of history, it'shard lo make rapid changes." In additionto the weight of tradition. Popescu pointsto the slowdown of innovation in theentire textile industry because of the costs

' OCTOBER S005

...we want to bringout of win

' Cool WooF has bfndeveloped, and w0ol

can be a trans-seasoialfiber—something

Consumers can considerwearing a n y H

of theof research and development. Again, woolis a fiber of limits—high costs bringlimits to production and processing, andalso bring limits to wool innovation.

Fiber"The current fashion is for a very fine,soft hand and very fine micron wool,"notes Popescu. "However, if that fashionchanges, you just can't change the sheepthat quickly." Popescu feels that one ofthe trends of the future will be the fur-ther genetic manipulation of the sheepand of their food in order to manipulate[he fiber product. "So far, selectivebreeding has been able to manipulate thecrimp and diameter of the wool fiber," hesays. "Since 2000 it has been possible toproduce shrinkproof fiber on the back ofa sheep."

According to Popescu, genetic engi-neering should be able to affect the woolfiber in other ways as well: specificluster, even specific color like whitershades, or pre-colored wool with no needfor dyeing (like the work being done oncolored cotton).

Several experts point to the develop-ment of the Optim fiber from Woolmark,which is made from wool by stretchingwool fibers and reducing their diameterand elitninating the crimp. "The woolcan be reduced at least three microns indiameter," says Popescu. He notes alsothat the Optim fiber has new propertiesthat are different than wool: a silkierhand, greater luster, and a capability of

more intense dyeing."Optim is not like traditional wool,

but a fiber derived from wool, withdifferent physical properties. This willhave a big impact on the wool marketbecause it will provide a new product forwhich wool is the raw material," says DeBoos. "It is of course more expensivethan normal wool, but is intended for ahigher value market. It is a very luxuri-ous fiber, and is often blended withcashmere and silk."

De Boos sees the future of wool as aluxury fiber. "It will be lighter andsofter," he says. "Additionally, we wantto bring wool out of winter. 'Cool Wool'has been developed, and wool can be atrans-seasonal fiber—something consum-ers can consider wearing any season ofthe year."

ProcessingPopescu says that there is interest inadding value to wool at the "top" stage."New developments in topmaking in-clude adding ehemieals to the sliver toget specific whiteness and luster duringthe preparation stage."

Lewis observes that work is beingdone to develop environmentally safechemistry for shrinkproofing woo! at thetopmaking stage as well. He also notesthe need for the development of insect-resistant wool. "Mothproofing agents areessential. Moth or beetle attacks willruin wool textiles. We have to developchemistry to modify wool to make it

indigestible to insects."Cardamone notes work on improving

the fiame resistant properties of woolwith new polymer systems and witharamid blends.

BlendsThe trend towards wool blends is in-creasing. "Wool/polyester blends willbecome more popular," Lewis predicts."As well as wool/cotton blends. Thereneeds to be more work done on one-bathwool/cotton dyeing. We'll need cleverchemistry to fix reactive dyes on cottonunder neutral pH."

"Wool blends beautifully wilh syn-thetics and cotton, as well as the highend luxury fibers like cashmere," agreesDe Boos. Sometitnes consumers want theproperty of the blended fiber to meetrequirements that pure wool can'tmeet—such as a wool/polyester suit thatcan be tossed in the washing machine.But often, wool blends arc sought for thefiber properties that the wool brings tothe mix. Wool hosts a plethora of proper-ties in combinations that "cannot beeasily itnitated by synthetics," saysHannemann. "There are things you justcan't do without wool,"

References1. CSIRO Textile and Fiber technology

website, www.lft.csiro.aii/achievemenls/chshrink.html, accessed August 2005.

2. Cardamone, J.M. and J. Yao, U. S.Patent No. 20040261/92, 2004.

OCTOBER 2005 WWW.AATCC.ORG