airlaid pulp nonwoven primer

AIRLAID PULPNONWOVENPRIMERCapabilities and End-usesMarket OutlookManufacturing Process

Association of theNonwoven Fabrics Industry

ACKNOWLEDGMENTS

INDA wishes to thank the following persons who edited this primer. These editorshave extensive experience with this technology and we appreciate their timeand efforts in preparing this primer.

Fraser EvansPresident of F. Evans Associates Inc., a Senior Associate of AMEC Forest IndustryConsulting, spent more than 30 years at Canfor in pulp and paper marketing.

Jeffrey HurleyManager, Nonwovens Division of Buckeye Technologies responsible for theproduction and sales of airlaid pulp materials. Formerly Mr. Hurley was withHoechst Celanese (Kosa).

Rob JohnsonPrincipal of Smith, Johnson & Associates, a consulting firm that focuses on thenonwoven industry. Earlier in his career, Mr. Johnson was with the airlaid pulpdivision of Scott Paper.

Ivan PivkoPresident, Notabene Associates Inc., a consulting firm that focuses on the airlaidpulp and related industries. Mr. Pivko was formerly the President and CEO ofMerfin Hygienic Products Ltd., now part of Buckeye Technologies.

Ed Vaughn, Ph. D., Clemson UniversityAs a professor with the School of Textiles at Clemson, Mr. Vaughn has manyyears of experience teaching about the nonwoven industry.

Inda would also like to thank the following companies for contributing materialsfor this primer.

Dan-Web

M&J

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AIRLAID PULPNONWOVENPRIMERCapabilities and End-uses

Market Outlook

Manufacturing Process

Prepared by:Ian Butler, INDA

Edited by:Fraser EvansJeff HurleyRob JohnsonIvan PivkoEd Vaughn

Association of theNonwoven Fabrics Industry

P.O. Box 1288, Cary, North Carolina 27512(919) 233-1210, Fax (919) 233-1282, www.inda.org

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Graphic design and printing by

Margaret M. ParkPRINTING by DESIGN

Raleigh, North Carolina, USA

Copyright© 2003 INDA, Association of the Nonwoven Fabrics Industry. Allrights reserved. This material may not be reproduced, in whole or in part, inany medium whatsoever, without express written permission of INDA,Association of the Nonwoven Fabrics Industry.

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TABLE OF CONTENTS

Introduction: .........................................................................................................Overview .................................................................................................... 1History of Technology ................................................................................. 2

Markets:Worldwide Volume ..................................................................................... 4Industry by Region ...................................................................................... 4Share of World Nonwoven Production ....................................................... 8Major End-Markets .................................................................................... 9

Performance Characteristics of Airlaid Nonwovens....................................... 11

Types of Fabrics Available .............................................................................. 13

Fibers and Materials Used in Airlaid Pulp Nonwovens .................................. 16

Success Stories:Absorbent Hygiene Cores .......................................................................... 20Wipes ......................................................................................................... 21Surgical Products ....................................................................................... 23

Airlaid Process: ....................................................................................................

Process Sequence ............................................................................................ 24

Web Formation ................................................................................................ 24

Bonding Methods ............................................................................................. 25

Future Directions ............................................................................................. 28

Glossary ........................................................................................................... 29

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INTRODUCTION TOAIRLAID NONWOVENTECHNOLOGY

The head forming section of Dan Web Air Laid Line

OVERVIEWThe term airlaid pulp nonwoven in this primer refers to a technology thatproduces a web from short fibers, most often from some form of softwood pulp.The process is also referred to as short fiber airlaid technology to distinguish itfrom the Rando Weber airlaid process that handles longer fiber lengths in the3.8-4.5 cm length range and are generally synthetic fibers, such as rayon orpolyester.

While the principal fibers used to produce airlaid nonwovens are fluff pulp madefrom softwood trees, other natural and short length synthetic fibers can be used.The process was originally conceived as a method of making paper without the

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FOOTNOTE:1 In his book, The Technology in Search of Markets, Ivan Pivko of Notabene AssociatesInc. details the full history of the airlaid technology from its inception through to current times.The book, written in a light-hearted manner, is packed with facts and information and is arecommended read for students of the airlaid industry.

use of water. In paper making, wood pulp is bonded principally by a chemicalreaction between the pulp’s natural cellulose and water. To enhance the paper’sstrength, small amounts of agents, such as rosin, are added to improve strength.In contrast, the airlaid pulp nonwoven technology uses latex resins, thermoplasticfibers or some combination of both to bond the web’s fibers into a fabric. Theprocess yields a paper-like fabric that is thicker or loftier, softer and generallymore absorbent with higher absorbent than paper. The addition of latex resinsor thermoplastic bonding fibers yields a material that is more tear-resistant,with increased tensile strength and higher abrasion resistance than the paperalternative… even when wet.

These attractive physical characteristics, plus a lower cost relative to alternativefabrics and nonwovens, make airlaid pulp nonwovens a very suitable fabric formany disposable products in the consumer and industrial/institutional markets.The main product categories where airlaid pulps are currently used are babywipes and other consumer and institutional/industrial wipes, absorbent coresin feminine napkins, table-top items and napkins.

Airlaid pulp is one of the fastest growing nonwoven technologies worldwide withdouble-digit volume increases during the 1990s. Continued high growth of thistechnology is forecast for many years onto the future.

HISTORY OF TECHNOLOGYIt is controversial as to where the airlaid technology really was originallydeveloped.1 The earliest traces of the technology date back to the 1940s whensome missionary companies experimented with various fibers and wood pulpon web forming machinery made at Curalator Co., now the Rando MachineCorporation. Commencing in the early 1950s or so, various individuals andorganizations located in such diverse countries as Russia, USA, Canada, UK,Japan, Finland, Denmark and Sweden, had a hand in developing the airlaidpulp technology. Many companies were intrigued by the possibility of making adry laid web from inexpensive wood pulp or wood pulp/fiber blends, which ledto airlaid development projects generally moving parallel one to another.

In the mid 1960s, Honshu of Japan designed a nonwoven technology to make a

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pulp-based cigarette filter material. The technology was successful and furtherairlaid developments led to making production lines to produce materials forthe disposable Oshibori wipes industry. And now, 40 years later, the originaltwo production lines are still in production.

About the same time, Johnson & Johnson’s Chicopee division (the fabricproduction division of Johnson & Johnson) was interested in the technology andcommissioned their Montreal, Canada plant to pioneer the development ofabsorbent core materials. Chicopee further developed the technology in theirChicago, IL plant and by the late 1960s had several lines producing airlaid pulpcore material for Johnson & Johnson’s baby diapers bypassing the need for topsheet. These early lines were scrapped when Johnson & Johnson exited thebaby diaper industry in North America.

Simultaneously and independently to Johnson & Johnson’s efforts, the Scott PaperCompany’s R&D was developing an airlaid technology and ultimately installeda modified Rando system at their Dover, DE site. Starting with various textilefibers, the company moved towards the use of wood pulp and was important incommercializing airlaid wipes made from a mix of pulp and synthetic fibers.The plant, now owned by Procter & Gamble, is still in operation.

Perhaps the key individual that led to the development and ultimate commercialsuccess of the airlaid technology was the prolific Danish inventor Karl Kroyer.Using an earlier patented invention by a Finnish inventor named Hjelt andpossibly some ideas from the Honshu technology in Japan, Kroyer madesignificant improvements to the technology to better the look and feel of theproduct. With further development, Kroyer’s first sale was an R&D line shippedto Kimberly-Clark’s research center in Neenah, WI. In 1970, Kroyer built asecond line, a 1.6 meter wide semi-commercial line for United Paper Mills ofDenmark. This line was shown to many companies that were evaluating thepurchase of technology and entering the airlaid pulp business.

While growth was not smooth during the next several years, a production linewas ultimately sold to American Can in Green Bay, WI. The commercial successof American Can’s Bolt consumer wipe product led the companies’ chiefcompetitor across town, Fort Howard Paper, to also install a similar productionline. About the same time, Scott Paper was developing their proprietary airlaidpulp technology using modified Rando equipment, as previously mentioned. Theindustry was well launched in North America and the success of the threecompanies developing consumer wipes is an important milestone marking thegrowth of the airlaid technology. Fort Howard and American Can operationswere merged in the mid 1990s and are now owned by Buckeye Technologies.

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It would be remiss to not mention the work of John Mosgaard, a principal ofDan-Web, which is an important supplier of the airlaid pulp technology.Mosgaard was an engineer and worked for Kroyer at one time, but decided togo on his own. One of his legacies to the industry was the development of therotary drum former … a technology employed on many airlaid lines worldwide.

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MARKETS

WORLDWIDE VOLUMEAirlaid pulp nonwovens have shown strong growth during the 1990s with theproduction of these materials almost tripling from 116,000 tonnes in 1992 toalmost 354,000 tonnes by the end of 2002. Considerable production capacityhas been added in several world regions and our expectations are that thetechnology annual output of airlaid pulp materials will rise to about 720,000tonnes by 2007.

Worldwide Airlaid Pulp Production(thousands of tonnes)

Source: INDA estimates

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INDUSTRY BY REGIONThe major producing regions of airlaid pulp nonwoven materials are NorthAmerica, Europe and Japan. These three regions together produce and consumeabout 90% of the world’s airlaid pulp materials. North America has been theleading producer of airlaid pulp nonwoven in part due to the close proximity ofsouthern pine, a wood pulp with many desirable properties, made from the fastgrowing Loblolly and Slash Pine located in the southeastern United States. Thetrees are grown on vast plantations to produce wood pulp and lumber. Growthcontinues in these three markets, but considerable airlaid pulp capacity is beingadded into other world regions, particularly South America, Middle East andChina.

Airlaid Pulp Production by Region(thousands of tonnes)


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North AmericaThe North American industry, which includes the U.S. and Canada, is the largestmarket for airlaid pulp nonwoven worldwide. This is due in part to the proximityto a vast wood pulp supply and in part to the early entry of several major airlaidpulp producers. These new airlaid pulp operations were owned by parentcompanies that produced paper and paper wipes, which had considerableknowledge and marketing savvy that helped to successfully develop and growthe market for the new air laid ventures.

In North America, there are nine airlaid pulp producers making products on anestimated 20 production lines. The combined production output in 2001 wasapproximately 126,000 tonnes. Airlaid pulp imports were considerable asdemand was higher than the industry’s ability to supply. The tight supply situationwas caused by the growing use of airlaid pulp as an absorbent medium infeminine sanitary napkin products and training pants. Also, at the same timedemand from the wipes industry for airlaid pulp materials rose swiftly with themany new product introductions. However, during 2001and 2002 the NorthAmerican industry added capacity totaling about 100,000 tonnes per year. Thiswas an enormous volume addition considering that the total North Americanairlaid pulp production in 1990, just a decade earlier, was just slightly in excessof 50,000 tonnes as shown in the previous figure.

At time of writing this primer, the North American industry was in an oversupplysituation. We expect the demand for airlaid pulp will continue to expand. Drivingthis growth will be the further adoption of airlaid pulp as an absorbent core andthe expanding use as a wipe material. A large market potential is absorbentcore material for baby diapers and further use in adult incontinent diapers.

EuropeEurope was the birthplace of this technology. Western Europe has six significantproducers and several smaller companies making product on 16 production lines.Airlaid pulp production from these companies during 2001 was about 120,000tonnes. Several countries have the technology, but the larger productioninstallations are in Germany, Sweden, France, Italy and Ireland.

Similar to the North American situation, airlaid demand has risen rapidlymatched by a subsequent rise in production capacity. The major end-marketsfor airlaid pulp are fairly similar, except that the volume share sold to theEuropean wipes industry is less than that sold into the North American wipesmarket. Disposable wipes made of airlaid pulp compete directly with

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hydroentangled nonwoven materials and European consumers have shown apreference for hydroentangled wipes in some applications.

Asia-PacificThe airlaid industry is most developed in Japan. There are four airlaid producersin Japan making product on at least eight production lines. Total annual airlaidcapacity in Japan is estimated at 30-35,000 tonnes, and the nation’s actualoutput runs about two-thirds that figure. Airlaid pulp is sold to a variety ofmarkets similar to those discussed for North America and Europe. A largemarket is cigarette filter media and another unique and significant market isthe volume consumed by oshibori wipes.

Considerable airlaid capacity was added to China in 2002 with the start-up ofa single production line that will be devoted mainly to producing absorbent core,but also capable of producing material for the wipes industry. Another line ofsimilar capacity is scheduled to come on-stream in 2003 and (at time of writing,there were at least domestically built lines installed based upon the Dan-Webrotary former technology. These large capacity expansions are expected todrive the country’s annual capacity to above 60,000 tonnes by the middle ofthe decade. China is the world’s third largest producer of newsprint and woodpulp availability is not an issue for producers in the region.

Other World MarketsOutside the previously mentioned regions, there are a few production linesscattered around the world in South America, Taiwan and Middle East. Thereason for the slow development in these other regions is because wipes, airlaidpulp’s largest end-use, are a luxury item and as discretionary income is low,demand for these types of wipes is low. Furthermore, while airlaid pulp is usedas an absorbent core in feminine products, absorbent cores can also be madefrom a formed fluff during feminine napkin production.

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SHARE OF WORLDNONWOVEN PRODUCTIONIn the early 1990s, worldwide production of airlaid pulp totaled close to 100,000tonnes, representing between 5.5-6% of total nonwovens production. By 2001,airlaid pulp’s production had tripled to about 300,000 tonnes, equivalent to 8%of total world nonwoven production. For the future, airlaid pulp demand by itstwo major markets, absorbent cores and wipes, are expected to drive thistechnology’s share to 13% of world nonwoven output by 2007 with outputexceeding 700,000 tonnes. Considerable expansion has already occurred inNorth America and China, but several high capacity projects are in the lateplanning stages in Europe and other world regions.

Airlaid Pulp Share of World Nonwoven Production(thousands of tonnes)


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MAJOR END-MARKETSThe major end markets for airlaid pulp materials include wipes (baby, personal,household and industrial), absorbent core materials, tabletop items (napkins,table cloths), medical dressings and oshibori wipes. Emerging productapplications include wet toilet paper, protective-cushioning materials forpackaging, filtration media, new composite wiping materials and food soakerpads (used under retail chicken packaging, for example).

Absorbent core materials and wipes account for almost 80% of airlaid pulpvolume in the North American market. Absorbent cores in adult incontinence,training pants and feminine care products account for 44% of all airlaid pulpconsumption. Airlaid pulp cores that contain super absorbents are thinner, moreabsorbent and depending upon how measured, are more cost effective thanconventional fluff pulp cores. While there are some baby diaper and trainingpant products on the market with airlaid cores, the technology still has notpenetrated these two markets to a significant degree. A major issue in switchingto an airlaid core is the immediate higher cost faced by the diaper producer.Airlaid pulp material is more expensive on a per kilogram basis compared toconventional fluff pulp cores, but these higher costs are offset to some extent bylower costs due to the thinner products requiring less packaging, lowertransportation and warehousing. Some research indicates improved baby diaperperformance and a product that is more comfortable. It is our opinion airlaidwill extend into the baby diaper industry as more airlaid production capacitycomes on stream. A portion of the growth forecast to 2007 includes this expectedshift to airlaid pulp cores.

The wipes industry is the second largest market for airlaid pulp in North America.Growth of airlaid pulp in this market has been exceptionally strong for severalyears as the industry expanded and new categories of wiping products wereintroduced to the consumer, industrial and institutional markets. Baby wipesare the largest wipes’ segment and consume 26% of airlaid pulp produced. Otherconsumer product introductions now account for a significant share of the businessand have driven increases in airlaid volume. Pre-moistened toilet tissue hasbeen launched by several major consumer products companies and could becomea significant new product category.

Another high growth wipes category is floor-cleaning products. There are anumber of disposable mops that use airlaid cores

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OTHER MARKETS

Disposable Handkerchief Meat packaging soaker pads

Filtration Media Moist toilet tissue

Protective Packaging Cosmetic pads

Fabric Stain Remover Pads Protective layer in liquid packaging

Table 1

A Selection of Other Airlaid Pulp Markets

World Airlaid Pulp Applications(2002 based upon tonnes)

Source: Notabene Associates, Inc.

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PERFORMANCECHARACTERISTICS OFAIRLAID NONWOVENS

The following provides some of the key attributes of airlaid technology usingwood pulp. Of course, the airlaid producer can modify the pulp’s characteristicsto meet the user’s specific needs.

Bulk and AbsorbencyOne of the most attractive features of airlaid pulp is its bulky or lofty nature.The airlaid process yields a web structure with a myriad of microscopic voids inwhich water or other liquids can be trapped and retained. Wood pulp is aninexpensive fiber relative to most alternate fibers, thus the producer can affordto make an airlaid product thicker for a given weight than most competitivematerials. The convenience, cost and hygienic benefits of a disposable wipemade from airlaid pulp are important reason why airlaid pulp replaces traditionalcloth wipes and other materials.

The same absorbency property makes this material a leading absorbent corefor disposable hygiene products as well as core materials for medical dressingsand sponges. The absorbency properties of fluff can be increased dramaticallyby adding superabsorbent materials to the fluff pulp.

SoftnessAirlaid pulp nonwoven is inherently soft due to the wood pulp fibers used andthe various emulsions used to bind them. The softness of the material is animportant reason for its use as an absorbent core in products such as femininenapkins, incontinent pads and medical materials. In some absorbent products,there is actually direct skin contact. Most core material is soft, but the materialcan be engineered with stiffness that can improve the fluid acquisitionperformance.

Airlaid producers can produce material that is strong when wet and yet stillsoft. Because of these properties and its reasonable cost, airlaid pulp is a leadingwipes material used by baby wipes, household, industrial and institutionalcleaning.

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Wet StrengthPremoistened wipes are impregnated with various solutions used to clean babies,kitchen, bathroom and windows. All these end uses require a material that willretain its strength when wet.

Wood pulp fibers are short and naturally bulky. Short fibers generally yield alow strength fabric. Airlaid pulp nonwoven’s strength is improved by using resinbinders and adding crimped synthetic fibers to the pulp blend. The binder andfibers result in an airlaid pulp material that is stronger than paper while retainingits softness. For example, typically an airlaid web will retain about 50% of itsstrength when wet, while paper’s strength retention is much lower. The syntheticfibers also aid the airlaid web to retain its bulk when wet.

ValueThe fluff pulp used by the airlaid process is made from a variety of trees. In aprice per kilogram basis, fluff pulp is one of the least expensive fibers incomparison to most other forms of natural and synthetic fibers.

Natural, Sustainable and BiodegradableFluff pulp is a natural fiber made from trees grown on massive tree plantations,which have been cultivated specifically for the making of construction lumberand fluff pulp. Many products, such as premoistened baby wipes andpremoistened toilet wipes, are flushable and biodegradable under the rightconditions.

Abrasion ResistanceOne of airlaid pulp’s significant competitors in wiping products is paper toweling.The use of resin binders improves the abrasion resistance as well as the strength.Airlaid producers can use soft latex binders for products where softness is desired,such as cosmetic remover pads, alcohol prep pads, and fine polishing cloths.

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TYPES OF FABRICSAVAILABLE

There are several methods used to bond airlaid pulp webs. The first and earliestform of bonding used latex resin to bind the fibers. Until the past few years, thismethod was the principal form of binding fibers and accounted for most of theworld’s production. During the 1990s, the use of thermal fusible synthetic fibersto bind the web’s fibers became the dominant system. It is fair to say that nowmost airlaid pulp production is multi-bonded, which combines latex bonding andthermal bonding to increase the end products strength and reduce dust fromloose fluff pulp.

A new bonding system gaining is commercial importance over the past fewyears marries an airlaid pulp web with a carded web usually made from syntheticfibers. In this system, the hydroentangling process bonds the two webs of fibersinto a single homogeneous material. A newly termed word for this compositeprocess is air lacing. In fact, this process is similar to spunlaced material madefrom a pulp tissue hydroentangled (bonded) to a web of synthetic fibers. Thedifference between the two processes is that air lacing uses loose fluff pulp whilespunlacing uses a preformed pulp tissue.

LATEX BONDINGIn latex bonding, the web of pulp fibers is bonded together by a latex resin thatis applied by a spray system. The sprayed web is then transported to a dryingsystem that drives off the moisture and the binder reacts with the cellulose toform a bonded network of fibers

This process is most suitable for webs with a low basis weight, say up to 50gsm, as the spray is unable to penetrate deeply into the fibrous web to bond it.Attempting to bond a web that is overly thick can lead to web delamination, asituation where the web splits down the middle into two pieces. End-productsthat use this form of bonding include premoistened and dry wipes, table topitems, some medical products, a large portion of cores used by feminine hygieneproducts and meat packaging soak pads.

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THERMAL BONDEDThermal bonded airlaid materials are bonded by means of thermoplastic fibersthat are intimately blended with the fluff pulp. Generally bicomponent fibersare used. The fibers are either a polyester or polypropylene core fiber with apolyethylene sheath containing an additive to improve the adhesion to thecellulose fibers. Crimped bicomponent fibers of 4 mm or 6 mm in length areblended homogeneously into the wood pulp forming a three dimensional web.The amount of bicomponent fiber added to the web can range from 5-35% ofthe total pulp/fiber blend, depending upon the end application. Generally theweb of loose fibers is lightly calendered to a specified thickness. The web istransported to a heated oven that melts the fiber’s polyethylene sheath, whichforms bonding points between the bicomponent fibers and the pulp. The bondingwill help hold in place any other materials in the pulp/fiber blend, such assuperabsorbent powders

Thermal bonded materials are suitable for any weight of material above 50grams, but are definitely necessary for fabric weights above 120 gsm. Thermalbonded materials are typically used as absorbent cores in absorbent hygiene,floor cleaning wipes or medical dressing products. Airlaid materials that arebonded exclusively by thermal bonding are not suitable for some end applicationsdue to surface dust and loose pulp fibers.

MULTI BONDEDMany webs today are multi bonded, which is a combination of latex bonded andthermal bonded. The web’s exterior layer receives a light application of latexbinder and the center of the web is bonded by use of thermoplastic fibers thatfuse to the wood pulp and each other during drying/curing of the web. The purposeof latex spray is primarily dust control … to reduce the amount of loose fiber orlint generated in subsequent converting processes.

POINT BONDEDA recent development is the point bonded method of bonding the airlaid pulpweb, which is bonding the web by means of high-pressure calenders. Thistechnology is also referred to by various names, the most common being X-bonded, hydrogen bonded and pressure point bonded. In the point bondedmethod the web is put through an engraved calendar bonding system. The heatand pressure of the calenders rolling together essentially fuses the pulp fibers

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together at the calenders’ engraved points. There can be some additional fusingfrom bicomponent fibers and superabsorbent materials, if present in the web.

An airlaid pulp web can be also calendar bonded by using smooth, unengravedcalenders. The resulting material is stiff, boardy and will resemble paper.

AIR LACINGAir lacing is a relatively new technology that is expected to increase inimportance. The term air lacing really refers to more than just the bondingmethod … as it also describes the type of nonwoven materials derived fromthe process. Air lacing has its roots in the hydroentangling (or spunlacing)technology. In the hydroentangling process, a lightweight, tissue paper is marriedto a web of carded synthetic fibers by high velocity jets of water that entanglethe two materials into a composite. Air lacing is essentially the same, exceptthat the process joins an airlaid web of pulp fibers (unbonded) to a carded webof synthetic fibers.

There are several advantages to the air lacing technology:

• The air laced nonwoven is an inexpensive composite material with goodabsorbency and higher tensile strength than an airlaid web.

• Substitution of a portion of the synthetic fibers with lower cost fluff pulpfibers yield as material that is very competitive in cost and performanceto a hydroentangled fabric that is made exclusively from synthetic fibers.

• The blending of wood pulp into the air laced material improves the web’suniformity.

Air laced materials have the look and feel of traditional textiles and major end-applications include wipes, surgical apparel and drapes, industrial disposableapparel and table top items.

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FIBERS AND MATERIALS USEDIN AIRLAID PULPNONWOVENS

PULP FIBERSThe prime fiber used in the airlaid technology is fluff pulp. Fluff pulp is a genericname referring to pulp that is obtained from several renewable plant sourcesincluding eucalyptus, flax, hemlock, spruce and pine. Fluff pulp is a naturalcellulosic fiber that has the advantages of low cost, excellent absorbency, opacity,softness and is readily dyeable. The pulp’s physical and chemical characteristicswill vary depending upon the species of the tree used, geographic growing area,pulping and bleaching process used and whether or not chemical additives havebeen added to the pulp to affect processing.

Large quantities of fluff pulp are also used to make the absorbent cores inabsorbent products, such as baby diapers, feminine napkins and other relatedproducts.

Most fluff pulp used in the airlaid process is obtained from pine trees, which areavailable in many regions globally. In North America, fluff pulp is obtained fromsouthern varieties of pine trees. The morphology of southern pine is quitedifferent from northern pine species due to the longer growing season and “softer”climate in the south. Southern pines produce thicker fibers and their pulp ispreferred in applications where good absorbency properties are required. Thetrees most commonly harvested to make fluff pulp are the Slash and Loblollypines. Slash pine, which accounts for higher volume, is grown on millions ofacres in tree plantations throughout Florida, southern Georgia and to a lesserextent in neighboring southern states. Trees on these plantations reach maturityin a relatively few years due to the favorable climate and fertile conditions.Indeed, a tree reaching 30 years can be harvested for construction lumber, whileyounger trees are used for pulping purposes. To give some measure of growthof these southern pine tree varieties, a fertile plantation acre of land will growabout two cords of wood per year, almost 50% more than a northern pinespecies.

The harder growing season in northern climates yields a wood with much thinnerfibers and cell walls compared to their southern counterparts. The northern

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pines are more ideally suited for lumber production and for certain printing andwriting papers, especially those requiring a strong web that will be subjected tothe stresses of high speed printing. Moreover, due to the thinner pulp fibers,northern pine pulp is much less absorbent than southern species of pine. InEurope, some quantities of pulp are produced in the Scandinavian regions whereforests are also cultivated specifically for lumber and pulp for paper production.

The worldwide demand for fluff pulp by absorbent cores and airlaid pulpproduction was about 3.5 million tonnes in 2002. This figure has been relativelystatic for several years, despite of the increased use of absorbent fluff byemerging world markets. The reason for no increase is because the use ofsuperabsorbent polymers within the absorbent core has lowered fluff pulpdemand. As well, the switch to lower weights of airlaid nonwoven cores haslowered pulp demand. However, total pulp demand is expected to rise, drivenby the growth of adult diapers in mature markets and development of absorbenthygiene industries in emerging markets. While there are a variety of pulpsources, southern pine from U.S. producers meets about 2.6-2.8 million tonnesof the 3.5 million tonnes of demand or roughly three/quarters of the total. Itshould be mentioned here that although our forecast is for a doubling of airlaidpulp production over the five-year period between 2002 and 2007, this doesnot mean a doubling of fluff pulp volume. The reason is that airlaid pulp used asa core material is replacing fluff pulp in the core area, so there is no net gain.

SYNTHETIC FIBERSSynthetic fibers are used as bonding fibers in airlaid pulp nonwovens and are animportant component of the air laced nonwoven process.

As indicated previously in the Thermal Bonded section, bicomponent syntheticfibers are the main fibers used to bind the pulp fiber web. The bicomponentfibers commonly used to bond these webs are a low melting temperature sheath,generally polyethylene (PE), surrounding a higher melting temperature core suchas polypropylene (PP) or polyester (PET). These sheath/core combinations areusually written as PE/PP and PE/PET. Generally an additive, such as maleicanhydride, is compounded into the PE prior to spinning the bicomponent fiber toimprove the covalent bonding with the cellulose fibers.

Fiber length can vary but most is in the 4-8 mm range. The longer lengthsgenerally yield a higher strength airlaid fabric than one made with shorter length.Bicomponent fibers are opened by a separate opening devise and are fed to theweb formation system where they are intimately blended with the wood pulpfibers.

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Air Laced WebsAs covered previously, the air laced nonwovens technology blends a cardedweb, generally of polyester or rayon fibers, with fluff pulp and then bonds thewebs together by hydroentanglement. The carding technology generally usesfibers in the 3.8-4.2 cm range.

SUPERABSORBENTSSuper absorbents are sorbent materials that can absorb many times the amountof liquid ordinarily absorbed by cellulosic material, such as wood pulp or cotton.The materials can absorb liquids anywhere between 10 and 100 times theirown weight, depending upon the liquid being absorbed and time. These materialsare used extensively in airlaid pulp materials that will be used as absorbentcores in feminine napkin, training pants, baby and adult diapers. The use ofsuperabsorbents reduces the amount of fluff pulp required and the resultingproducts are slimmer, lighter weight and easier fitting.2 Further, the slimmersize allows for smaller packaging sizes thereby reducing transportation andwarehousing costs.

Superabsorbent materials are available in a powder or granular form that areadded to the fluff pulp in the forming process prior to the pulp being bonded.These are generally referred to as superabsorbent powders (SAP).

The use of superabsorbent fibers (SAF) is increasing. As with SAP, these fibrouspolymers that can absorb liquids 10-100 times their weight and are mixed intothe fluff pulp at web’s forming heads.

LATEXLatex is a resinous bonding agent used by several nonwoven technologies.Relevant to airlaid materials, the latex resin is dissolved or is in a colloidaldispersion within water, which is then sprayed or foamed onto the web. Latexacts as the glue that holds the loose web of fibers together. The range of bindermaterials is wide and the more important are butadiene polymers, acrylicpolymers and vinyl polymers.

FOOTNOTE:2 The amount of pulp used within the average baby diaper in the 1970s and 1980s was about45-50 grams, whereas today the amount used is 15-20 grams per unit.

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The latex binder has a major influence on the physical properties of the finalairlaid fabric. Thus, the requirements of the finished product or end-usedetermine the selection of the type of bonding agent. Below are some of thefabric’s characteristic that are influenced by the latex binder:

• Draping qualities• Fabric strength/resilience, especially when wet• Elasticity• Absorbency, hydrophilic or hydrophobic properties• Aesthetic properties such as softness or “hand”• Anti bacterial or anti fungal properties• Chemical resistance, particularly with moist cleaning wipes• Color

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Success Stories

ABSORBENT HYGIENE CORES

A key component of anabsorbent hygiene product is theabsorbent core. The function ofthe absorbent core in babydiapers, training pants, femininesanitary products and similarproducts is to acquire the urineor other bodily fluids and act asa reservoir to hold it. Fluff pulphas always been the keycomponent of the core, butincreasingly superabsorbentpolymers are being added to thecore to reduce the amount offluff pulp required and be a moreeffective means of holding largerquantities of bodily fluids.Absorbent cores have until thepast few years been formed onthe production line making theproduct (diapers, femininenapkins, etc.). However, thedevelopment of airlaidnonwoven cores has led to a new generation of thinner feminine hygiene productsthat have ultra thin cores. By 2002, almost all feminine hygiene products wereusing airlaid cores exclusively or the plants were being converted over to useairlaid material. These thinner cores are now finding their way into adultincontinence and training pants products. Adults appreciate airlaid cores, asthe hygiene products are thinner, more discrete and capable of handling a largervolume of urine. The product is more acceptable to children at the potty trainingstage as the thinner training pants have an appearance similar to regularunderwear. Absorbent product manufacturers are also reviewing thereplacement of machine-formed absorbent cores with the airlaid pulp nonwovenin baby diapers.

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Success Stories

WIPES

While several types of nonwoven technologies are used in making disposablewipes, airlaid nonwoven have captured a significant share of the total businessbecause of its low cost relative to the competing materials plus the physicalattributes of softness, bulk, absorbency and strength. Consumer wipe productshave proliferated during recent years and are generally classified into threecategories of product: baby wipes, personal wipes (such as, cosmetic, incontinenceand general purpose) and household cleaning wipes. The household segmenthas grown rapidly over the past several years and includes anti-bacterial wipesused in the kitchen and bathroom areas, furniture polish wipes, automotivecleaners, mop heads, general cleanup and dish cloths. In industrial wipingapplications, airlaid nonwovens offer the advantages of lower cost, cleanlinesscompared to conventional reusable textile wipes and higher strength andabsorbency than paper wipes.

CONSUMER WIPESThe airlaid pulp technology is a major part of the premoistened disposable wipesbusiness. This consumer wipes business is large and growing in North Americaand valued at more than a billion dollars at the retail level and consuming morethan 1.5 billion square meters of nonwoven wipes materials. Consumer wipeshave had significant growth that spanned the 1990s. Baby wipes, used at diaperchange time, are the leading consumer wipes segment accounting for almost60% of all consumer wipes volume in terms of nonwoven fabric consumed.

In the developed markets of North America, Europe and Japan, the baby wipes’market growth has slowed in recent years as the market reached maturity.However, the declining growth of the baby wipe segment has been offset by thegrowth performance of the personal wipes segment, which includes body wipes,incontinence wipes, cosmetic wipes and moist tissue … all products that haveshown significant expansion. In part, the decline of baby wipe growth can beattributed to its cannibalization by these non-baby wipe products. Some of thesepersonal wipes segments have displayed explosive growth with numerousproduct introductions.

Several nonwoven technologies are used in making disposable wipes, but airlaidpulp has the advantage of low cost, moderate strength and good absorbency.

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Due to its softness, airlaid pulp is used widely in premoistened baby wipes.Airlaid is versatile and is used in some household wipes, such as the “hardsurface” and anti-bacterial wipes designed to clean and disinfect the kitchenand bathroom areas.

Airlaid nonwovens are used for many household consumer wipes.

INDUSTRIAL AND INSTITUTIONAL WIPESNonwovens are replacing disposable rags, shop towels and paper wipes ingeneral manufacturing, such as printing, automotive, aerospace and many otherproduction areas. Airlaid pulp is attractive due to low cost, bulk, absorbencyand product consistency.

A large market for airlaid nonwoven in Japan is the “oshibori” towel, which is awarm premoistened hand towel used before eating. The oshibori is a popularcustom spreading to other cultures. Occasionally, travelers will find oshiboriwipes provided on western culture airlines.

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Success Stories

SURGICAL PRODUCTS

Nonwovens are used widely by the medical systems in North America, Europeand Japan. Many healthcare providers prefer sterilized, single-use surgicalapparel, patient drapes and other single-use products. Single-use products areinexpensive and provide good value in protecting medical personnel and patientsagainst the spread of infectious diseases or other pathogens transmitted bybodily fluids or blood. The costs of these single use items are competitive withreusable gowns, which must be laundered and have a limited life to retain theirbarrier properties. Single-use surgical apparel accounts for approximately three/quarters of surgical apparel in U.S. hospitals and about 40% in Canada andsome northern European countries.

The healthcare industry uses a variety of nonwoven materials in their single-use products. Hydroentangled nonwovens have been a key supplier to thismarket. The similar air laced technology is expected to be a major source ofnonwoven material for the surgical and related markets.

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AIRLAID PROCESS

Full swing lineLatex spray bonding, thermal bonding, hydrogen bonding

or any combination of the processes

PROCESS SEQUENCEThe process for making an airlaid nonwoven is similar to that of making a cardedweb and nonwoven. First, the fiber is opened, then the web is formed and thethird and final step is the bonding. Post treatment to the airlaid nonwoven is apossible fourth step prior to converting the nonwoven into a finished product.The page opposite illustrates the technologies of the two principal machineryproducers: Dan-Web and M & J, both located in Denmark.

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FLUFF PULP DEFIBRATIONThe first step in the process is fluff pulp defibration. To save space and shippingcosts, fluff pulp is purchased in a highly compressed roll form. The bleachedwhite pulp is quite thick … a millimeter or two … and has a cardboard-likefeel. This material is fed into a hammermill, a device that has a series ofhammers rotating at high speed to separate the compressed pulp into looseindividual fibers. The loose pulp is then transported pneumatically to the webforming system.

WEB FORMATIONThe loose pulp delivered from the hammermills is fed into the web formationdevice. There are two web formation technologies. In one system, the webformer is a coarse screen into which the fluff pulp is fed. An agitator forces thepulp through the screen and the pulp falls like snow to the collecting screenbelow. M&J Fibretech of Denmark builds this technology.

A second web formation system uses a drum former. The Danish producer,Dan-Web, builds this technology. In drum forming, the pulp passes through aseries of holes or slots that are in a cylinder that spans the width of the collectionscreen. There are two cylinders in each forming head that are counter-rotatingat high speed and each has an agitator inside to randomize the fiber distribution.Drum formers do not always have a nit return, relying on high defibration at thehammermills to eliminate the nits or fibers that have bundled together in theprocess.

In either system, the fibrous pulp is kept in place by a vacuum below the collectionscreen. Generally a production line will have multiple web former systems.After passing one former, the web moves onto subsequent formers for additionallayers of pulp.

Other additives, such as bicomponent fibers or superabsorbents are also fedinto the web formers for blending with the fluff pulp. Airlaid production linesusually have provisions to vary the additives for each former, thus giving theman ability to have a layered material where the function of some layers canperform different tasks. For example a bottom layer of an absorbent core webcould contain more superabsorbent and so become a larger reservoir.

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FOOTNOTE:3 Embossing can also be done after the oven bonding procedure if the web is a thermally bondedstructure, especially a web with a high level of bicomponent fiber.

Three-head forming system from M&J

WEB CONSOLIDATIONPrior to bonding, the web goes through a small step, which includes compactionand embossing. Compaction is a light calendering to provide some integrity orcohesiveness to the web. At this stage, embossing of the web is usually done,particularly if the web is to be latex bonded only. Embossing patterns could bea company logo or teddy bears and such for baby wipes.3

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BONDING METHODSAs covered in a previous section, there are five principal bonding methods: latexbonding, thermal bonding, multi bonding, point bonding and air lacing.

Latex BondingThere are two methods of applying the latex binder to the web. In one system,the compacted web is carried on the forming screen and first sprayed with alatex resin on one side. The web is dried in an oven and then flipped to itsreverse side to receive a second a binder spray. The web goes through a seconddrying operation, which cures the binder and is then sent to the slitting/wind upsystem.

The second method of binder application does not flip the web but applies thebinder spray from the bottom side of the web prior to the second drying oven.In this system, the second drying oven which has an “up” air flow holding thedry, already sprayed and cured side of the web in place against the top of thedrying wire. A second spray of binder is applied to the bottom side.

A relatively recent development is the use of foam bonding. Rather than sprayingthe latex, the web is led into a bath of latex resin that is in a foamy state. Thereare several advantages using a foam application system, but the main reasonis cleanliness as in a spray system there is always some over spray, which cancontaminate nearby equipment and requires diligent maintenance. At time ofwriting, only a few firms were using this technology and it is limited to heaviermaterials generally exceeding 100 gsm.

Most airlaid webs are dried using a through-air drying method. In this type ofsystem, heated air is passed through the moist web evaporating the binder’swater content. Through-air drying produces a bulky and soft fabric. Drum dryingis used on a small percentage of airlaid materials. The web is fed through aseries of heated drum rollers that drive off the water content. Drum dryingresults in a stiffer product resembling paper. Fabrics containing a higherpercentage of fluff pulp in the mix require more residence time in the dryer.

Thermal BondingThe web of wood pulp and synthetic fibers is transported to a through-air oven,which softens and melts the sheaths of the bicomponent fibers to the point wherethey bind or fuse together the various web components. The web is calenderedto correct the web’s thickness, cooled and led to the wind up system.

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Multi BondingMulti Bonding is a combination of both systems. The web’s center portion isthermal bonded and a light latex bonding is sprayed on both sides of the weband dried. As explained earlier, the purpose of multi bonding is to reduce thelint and dust generated during conversion to a finished product.

Air LacingIn the air lacing process, an airlaid web of wood pulp is married to a web formedby another nonwoven web formation technology, such as carding or spunlaid.(See the following drawing.) The combined webs are bonded together by thehydroentangling bonding process. Hydroentangling is a bonding method wherestreams of high-pressure water emitted from closely spaced nozzles are directedat the fibrous web. The intensity of the water streams on the supported webentangles and interlocks the fibers to yield a cohesive nonwoven material. Thematerial is subsequently dried and the finished nonwoven material has goodaesthetic and physical properties of softness, drapability, absorbency and tensilestrength. The blending of wood pulp with synthetic fibers generally ranges froma 60/40% blend to a 40/60% blend, depending upon the final application. Theapplications include premoistened and dry wipes, medical and other protectiveapparel.

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FUTURE DIRECTIONS

Airlaid pulp technology has a bright future. The product’s physical aesthetics ofsoftness, bulk and absorbency at an economical price makes this an idealmaterial for many product applications.

Worldwide, this technology has exhibited rapid growth over the past decadeand the growth rate is anticipated to continue. Leading the growth has been theincreasing use of airlaid pulp cores by the absorbent products industry. Airlaidpulp cores caught on quickly after introduction and now dominate the femininenapkin market in many world regions. Several producers of training pants andadult incontinent products around the world are now using airlaid pulp cores.Absorbent cores made from airlaid pulp are more expensive on a per kilogrambases than the traditional production line formed absorbent core. But there aremany advantages associated with switching to airlaid cores, such as lesspackaging, lower shipping cost, less warehouse space, improved productperformance, possible superior performance, less raw materials and theelimination of hammermills and superabsorbent feeders in the production plant.More importantly, is the superior thinness of diapers made with airlaid cores.We expect baby diaper producers will shift a portion of their diaper productionto airlaid pulp cores, replacing the traditional production line formed core. Inthe short term, it is most probable that only a portion of baby diapers will beconverted to airlaid cores in those product segments where the purchaser isperformance and style and less influenced by cost, say as with premium productsor new born products.

Wipes will remain an important end-market for airlaid pulp. Until thedevelopment of the airlaid core business, wipes were, by far, the most importantmarket for airlaid pulp material. Over recent years, the expanding use of variousconsumer and industrial/institutional wipes has driven the wipes industry withannual growth rates in the 6-7% per year. Airlaid pulp is an important materialused by the industry because of its relatively low cost and is expected to benefitfrom the industry’s expansion.

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GLOSSARY

Absorption: A process in which one material (the absorbent) takes in or absorbsanother (the absorbate). The liquid or a gas is absorbed into a porous substanceand retained.

Acquisition and distribution layer: (also referred to as sub-layer) a nonwovenwicking layer under the top sheet (or face fabric) of an absorbent product, whichspeeds the transport and distribution of fluids throughout the absorbent core.

Additives: Chemicals added or incorporated into materials to give them differentfunctional or aesthetic properties, such as flame retardancy and softness.

Adhesion: The force that holds different materials together at their interface.

Aesthetics: Properties of fabrics perceived by touch, sight, smell and sound.Examples are hand, drape, texture, rustle, color and odor.

After treatment (Finishing): Chemical or mechanical processes carried outafter a web has been formed and bonded to enhance functional or aestheticproperties. Examples are embossing, crêping, softening, printing and dyeing.The term also includes slitting to narrower widths and rewinding to desired rolllengths.

Air forming: See Airlaid.

Air laying, Airlaid process: A nonwoven web forming process that dispersesfibers into a fast moving air stream and condenses them onto a moving screenby means of pressure or vacuum.

Airlaid nonwoven: An airlaid web that has been bonded by one or moretechniques to provide fabric integrity.

Airlaid web: A web of fibers produced by the airlaid process.

Airlaid pulp: An airlaid nonwoven that is produced with fluff, wood pulp. Theweb can be bonded with resin and/or thermoplastic resins dispersed within thepulp.

Bacteriostat: Chemical additive that limits or prevents the growth of bacteria.

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Basis weight: The weight of a unit area of fabric. Examples are ounces persquare yard and grams per square meter.

Bicomponent fibers: Fibers made of two different polymers extruded intoone filament (core within a sheath or side by side are examples). One type ofbicomponent fiber is produced using two polymers so chosen that one componentsoftens at a lower temperature to act as a binder while the other componentmaintain the web’s structural integrity. A second type of bicomponent fiber issplittable and with some form of mechanical energy applied, such as thehydroentangling technology, will separate into finer denier fibers.

Binder: An adhesive substance used to bind a web of fibers together or bondone web to another. The adhesive can be in a solid form (powder, film or fiber),foam, or in liquid form (emulsion, dispersion, solution) to bond the constituentelements or enhance their adhesion.

Binder content: The weight of adhesive used to bond the fibers of a web together– usually expressed in dry weight as a percent of the fabric weight.

Binder fiber: Fibers with lower melting points than other fibers with a highersoftening point or non-melting fibers. Upon the application of heat and pressure,these fibers soften and adhere to other fibers in the web, thereby acting as abinder. Some binder fibers can be bicomponent. A solvent (e.g. water) canactivate some binder fibers, which may not be thermoplastic.

Biodegradable: The ability of a substance to be broken down by bacteria.

Blend: A combination of two or more fiber types in making yarn or fabrics.

Boardy: The quality of stiffness in describing the hand of a fabric.

Bonding: The process of combining a fibrous web into a nonwoven fabric bymeans of resins (e.g. adhesives or solvent) or physical (e.g. mechanicalentanglement or thermal adherence). The bonding may be all over or restrictedto predetermined, discrete sites.

Bond strength: Amount of force needed to separate layers in a laminatedstructure or to break the fiber-to-fiber bonds in a nonwoven.

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Calender: A machine used to bond sheets of fabric or film to each other or tocreate surface features on these sheets. It consists essentially of two or moreheavy cylinders that impart heat and/or pressure to the sheets that are passedbetween them. The rollers can be mirror-smooth, embossed with a pattern orporous.

Calender bonding: Thermally bonding a web of loose fibers by passing themthrough the nip of a pair of calender rollers, of which one or both are heated.Plain or patterned roller may be used. (see Point Bonding)

Calendering: A mechanical finishing process used to laminate and to producespecial surface features such as high luster, glazing and embossed patterns.

Capacity: It is the maximum production output a nonwovens machine isdesigned to deliver.

Card: A machine designed to separate fibers from impurities, align and deliverthem to be laid down as a web or to be further separated and fed to an airlaidprocess. The fibers in the web are aligned with each other predominantly in themachine direction. The machine consists of a series of rolls and drums that arecovered with many projecting wires or metal teeth.

Card clothing: The wire teeth or serrated flutes that cover the working surfacesof a card.

Carded nonwoven: A nonwoven produced from a carded web that has beenbonded by one or more technologies to provide fabric integrity.

Carding: A process for making fibrous webs in which the fibers are alignedeither parallel or randomly in the direction that the carding machine producesthe web (see Machine direction).

Cellulosic fibers: Made from plants that produce fibrous products based onpolymers of the cellulose molecule. Cotton plants produce separate cellulosefibers. Wood pulp is made by mechanically and chemically separating woodfibers. Rayon is made by dissolving vegetable matter, generally wood pulp, ina solution and extruding the solution through spinnerets into a chemical baththat regenerates the filaments. Some other cellulosic fibers are flax, jute andramie.

Chemical bonding: See Resin Bonding.

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Chemical finishing: Processes that apply additives to change the aestheticand functional properties of a material. Examples are the application ofantioxidants, flame-retardents, wetting agents and stain and water repellents.

Chemical properties: The response of a fiber to chemical environments suchas acids, bases, or solvents.

Clump: A knot of fibers in a web resulting from improper separation of thefibers.

Coform: The formation of a nonwoven web through the concurrent use ofelements from at least two different web formation technologies.

Coating: Application of a liquid material to one or both surfaces of a fabric,which is followed by drying or curing.

Cohesion: The resistance of like materials to be separated from one another.Examples are: The tendency of fibers to adhere to each other during processing,the resistance of a web to being pulled apart, and the resistance of a componentof a laminate to being torn apart when the adhesive interface in the laminate isbeing stressed.

Composite material: Combination of two or more distinct materials having arecognizable interface between them.

Composite nonwoven: Term used when the essential part of the compositecan be identified as a nonwoven material. If the essential part can not beidentified, the term composite nonwoven is used when the mass of the nonwovencontent is greater than the mass of any other component material.

Converter: An organization that takes nonwoven fabrics supplied in rolls andprovides and an intermediate processing step, such as slitting, dyeing, coating,chemical finishes and printing. The fabric is then shipped to the finished productsmanufacturer.

Curing: A process by which resins, binders or plastics are set into or ontofabrics, usually by heating, to cause them to stay in place. The setting mayoccur by removing solvent or by cross-linking so as to make them insoluble.

Decitex (Dtex): Weight in grams of 10,000 meters of a fiber. It is one-tenth ofa tex (see Tex).

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Delamination: Tendency of a fabric to be pulled apart (layer separation) bynormal surface forces or shear tensions.

Denier: The measure of a weight per unit length of a fiber. Denier is numericallyequal to the weight in grams of 9,000 meters of the material. Low numbersindicate a fine fiber sizes and high numbers indicate coarse fibers sizes. The texsystem is used in countries outside the United States. A tex is numericallyequal to the weight in grams of one kilometer of fiber. It can be calculated bydividing the denier by nine.

Disposables: A general classification of end-markets where the product madefrom the nonwoven has a relatively short life. Examples of some of the majorcategories are cover stock for baby diapers and sanitary napkins, wipes, fabricsoftener, medical apparel and associated items and filters.

Drape: The ability of a fabric to fold on itself and to conform to the shape of thearticle it covers.

Dry forming or dry laying: A process for forming a web from dry fibers byusing carding equipment. Air laying refers to the formation of random webswith a stream of air.

Dry laid nonwoven: Dry laid web of fibers that has been bonded by one ormore bonding techniques to produce a fabric with integrity.

Dry laid web: A web of fibers produced by the dry laying process.

Drying cylinders: Drying cylinders are used by the resin bonded process. Thewetted, loose web is passed over the heated revolving cylinders to drive off thewater leaving the cured resin that bonds the web.

Durables: A general classification of end-markets for nonwoven materials. Themain characteristic of these markets is that the end products have a long lifeand are more or less permanent. The larger of these markets include apparelinterlining, automotive, home furnishings and bedding construction materials,carpeting, geotextiles and roofing material markets. See also Long-Lifeproducts.

Embossing: A process whereby a pattern is pressed into a film or fabric, usuallyby passing the material between rolls with little clearance, and where one orboth rolls has a raised design. At least one of the rolls is usually heated.

Emulsion: A suspension of finely divided liquid droplets within another liquid.

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Entanglement: A method of forming a fabric by wrapping and knotting fibersin a web about each other, by mechanical means, or by the use of jets ofpressurised water, so as to bond the fibers. See Hydroentangling.

Fabric: A sheet structure made from fibers, filaments or yarns.

Fiber: A unit of matter characterized by a high ratio of length-to-width. Materialsthat can be spun into yarn or made into fabric by interlacing (weaving),interlooping (knitting), or interlocking (bonding). Discontinuous fibers are referredto as “staple fibers” with lengths designated in inches or millimetres. Typicaltextile fibers have length-to-width ratios in the order of 1000 to 1, are longerthan one inch, have diameters greater than 10 microns, and mass-per-unit-length (linear density) values in the order of one gram per thousand meters.

Fiber distribution: In a web, the orientation (random or parallel) of fibers andthe uniformity of their arrangement.

Filament fibers: Filaments are extruded fibers produced from a variety ofpolymers. Filaments are continuous fibers that are produced by forcing a moltenpolymer through a spinneret. If cut to a shorter length, say 3.8 cm, the termfilament fiber changes to “staple” fiber.

Filament yarn: A yarn made of continuous filaments assembled with or withouta twist.

Finish: Substance added to fibers and textiles, in a post-treatment, to changetheir properties. Examples are lubricants and flame retardants.

Fusing: Melting or bonding together of fibers or fabrics.

gsm: Grams per square meter

gsy: Grams per square yard

Hand: Qualities of a fabric perceived by touch, e.g., softness, firmness, stretch,resilience and drape.

Hydroentangling, Hydroentangled: See Spunlace bonding

ISO: Acronym for the International Standards Organization based in Switzerland.

Latex: Either a naturally occurring milky appearing fluid from which rubber ismade or a dispersion of a synthetic polymer in water. Typically used as binders.

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Latex Bonding: See Resin Bonding.

Lint: Particles and short fibers that fall off a fabric product during the stressesof use.

Loft: The properties of bulk and resilience of a fabric or batt.

Long-life nonwoven: Synonymous with Durable nonwoven.

Machine direction: The long direction within the plane of the fabric that is inthe direction in which the fabric is being produced by the machine.

Man-made fibers: Another term for synthetic fibers.

Natural fibers: Fibers made directly from animals, vegetables or minerals.Examples are silk, wool, cotton, flax, jute, ramie and asbestos.

Neps: Small knots of tangled fibers that were not separated before forming theweb.

Nip: The line of close contact between two calender rolls between which afabric or web passes.

Nonwoven fabric: A fabric made directly from a web of fiber, without theyarn preparation necessary for weaving and knitting. In a nonwoven, theassembly of textile fibers is held together 1) by mechanical interlocking in arandom web or mat; 2) by fusing of the fibers, the case of thermoplastic fibers;3) or by bonding with a bonding medium, such as starch or synthetic resin.Initially, the fibers may be oriented in one direction or may be deposited in arandom manner. This web or sheet is then bonded together by one of the methodsdescribed above. Fiber lengths can range from 0.25 inch to 6 inches for crimpedfibers up to continuous filament in spunbonded fabrics.

:On-stream: See Start-up.

Opening: A preliminary operation whereby staple fiber is separated sufficientlyfrom its lap or baled condition so that it can be fed to the web forming part ofthe process.

Physical property: The response of a fiber to physical forces.

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Polyester fiber: A manufactured fiber in which the fiber-forming substance isany long chain synthetic polymer composed of at least 85% by weight of anester of dihydric alcohol and terephthalic acid (FTC definition). The physicalproperties of polyester fiber are excellent strength, high abrasion and resiliencewith good chemical resistance to acids, solvents and oxidizing agents. Majorend uses for polyester staple fiber are fiberfill, wipes, and durable nonwovens,such as geotextiles, automotive and carpeting. Spunlaid polyester is found infabric softener substrate, automotive carpeting, modified bitumen roofing andvarious durable end-markets.

Polymer: A liquid or solid substance made by chemically linking macromoleculestogether in chains. High polymer denotes substances made from very longchains. Crosslinked polymer describes a substance in which there aremolecular links between chains. Polymerization is the process for making thesepolymers.

Polyolefin: A fiber made of long-chain polymerized olefin of at least 85% weight,from such monomers as ethylene, propylene or other olefins.

Polypropylene fiber: A manufactured, olefin fiber made from polymers orcopolymers of polypropylene. One attractive physical characteristic ofpolypropylene is its specific gravity of less than one, which results in a largerarea volume yield per kilogram or pound of resin or staple fiber compared tocompetitive fibers. Polypropylene has a relatively low melt temperature thatrestricts its uses in many nonwoven markets, but it has good strength properties,softness, and chemical resistance to strong acid and alkalis. Major nonwovenmarkets for staple and spunlaid polypropylene include cover stock, medicalapparel and related, geotextiles, carpeting, blankets, automotive and variousother durable markets.

Pulp: Short cellulose fibers made from wood or cotton.

Rayon fiber: A manufactured fiber composed of regenerated cellulose, as wellas manufactured fibers composed of regenerated cellulose in which thesubstitutes have replaced not more than 15% of the hydrogen atoms of thehydroxyl group (FTC definition). Rayon is manufactured from the cellulose foundin vegetable matter, the major source being wood pulp and cotton linters. Thecellulose is dissolved into a viscose solution and then extruded through a wet-spinning system to coagulate the filaments. The principal physical properties ofrayon are moderate strength, softness, luster, hydrophilic and ease of dyeing.The major nonwoven market is wipes.

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Resin: Any of a group of solid or semi-solid materials made by chemicalsynthesis. The materials are often used in plastics or production of syntheticfibers (see Polymer).

Resin bonding: A common method of web bonding by using chemical agents,which may include adhesive resins and solvents. Most common is resin bonding.Latex resins (adhesive) are applied to the web by a variety of methods: dippingthe web into the latex and removing the excess, spraying, foaming or printingbonding. The resin is usually in a water-based solution, so this bonding processrequires heat to remove the water to dry and set the binder into the fabric.This is sometimes referred to as “latex bonding”.

Roll goods: Fabric rolled up on a core after it has been produced. It is describedin terms of fabric weight and the width and length of the material on the roll.

Short-life nonwoven: Synonymous with Disposable nonwoven.

Spunbond, Spunbonded: A spunlaid technology in which the filaments havebeen extruded, drawn and laid on a moving screen to form a web. The term isoften interchanged with “spunlaid”, but the industry had conventionally adoptedthe spunbond or spunbonded term to denote a specific web forming process.This is to differentiate this web forming process from the other two forms of thespunlaid web forming, which are melt blown and flashspinning.

Spunbond nonwoven, Spunbonded nonwoven: A fabric formed fromspunbonded process that has been bonded by one or more methods to providefabric integrity.

:Spunbond/Melt blown composite: A multiple layer fabric that is generallymade of various alternating layers of spunbond and melt blown webs: SMS,SMMS, SSMMS, etc.

Spunlace bonding, Spunlaced bonding: The method of bonding a web byinterlocking and entangling the fibers about each other with high velocity streamsof water (synonymous with Hydroentangling). The web or fabric may haveother bonding methods in addition to spunlacing. Spunlacing, not to be confusedwith spunlaid, is generally produced from a web made up of staple fibers froma dry formed, carded system, but small quantities of spunlaced bonding aredone on production lines that use a wet laid forming process. A recent technicaldevelopment is the production of a spunlaced nonwoven from a spunlaid,continuous filament web.

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Spunlace nonwoven, Spunlaced nonwoven: A fabric produced by thespunlaced technology. Spunlace is synonymous with hydroentangling.

Staple fiber: Refers to natural or synthetic cut fibers. The work “staple” isused by the textile industry to differentiate cut fibers from continuous filamentfibers, such as that used in the spunlaid process. Synthetic staple fibers used inthe needlepunched process are generally about 3.8-4.8 cm in length. The fiberlengths of natural fibers, which include wool, cotton, choir, jute and several others,vary considerably.

Start-up: The time when a new production line is finally put into commercialproduction after the production line is commissioned. This term is synonymouswith “on-stream”.

Superabsorbent: A sorbent material that can absorb many times the amountof liquid ordinarily absorbed by cellulosic materials, such as wood pulp, cottonand rayon.

Synthetic fiber: A man-made fiber, usually from a molten polymer or from apolymer in solution.

Tear strength: Resistance of a material to being torn.

Tensile strength: The strength of a material when subjected to either pullingor to compressive stress. It measures the stress a material can bear withoutbreaking or tearing.

Tex: A metric measure of the weight per unit of a fiber. It is numerically equalto the weight in grams of one kilometer (1000 meters) of the material. It is alsoequal to the denier divided by 9 (see Denier).

Thermal bonded/Thermobonded: A web of fibers bonded by a thermal bonding(thermobonding) process.

Thermal bonding/Thermobonding: A technique for bonding a web of fibersin which a heat or ultrasonic treatment, with or without pressure, is used toactivate a heat-sensitive material. The material may be in the form of homofilfibres, bicomponent fibers, fusible powders, as part of the web. The bondingmay be applied all over (e.g. through or area bonding) or restricted topredetermined, discrete sites (e.g. point bonding).

Thermoplastic: A plastic that melts when heated.

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Thickness: The dimension of a sheet or lamina measured perpendicular tothe plane of the sheet.

Through-air bonding: A bonding system that that uses high temperature airto fuse the web’s fibers. There are two basic systems: blowing hot air throughthe web in a conveyor oven or passing heated air through the web on a rotatingdrum (illustrated below). Fabrics made from bicomponent fibers or blends ofbicomponent and regular fiber are often bonded by through-air bonding systems.This method is sometimes referred to as air-through bonding.

Throughput: Amount of output or production per unit time.

Weak web: A term generally used in the context of web formation in a cardingprocess. It refers to the low cohesion of the fibers to one another and thus theweb does not have the strength to transfer from one working component toanother in the carding process. This situation can be caused by a number offactors, such as poor fiber finish or humidity problems.

Web: A sheet made by laying down and assembling fibers or by creating holesor cracks in a plastic film.

Web consolidation: See Bonding

Wood pulp: Cellulosic fibers used to make viscose rayon, paper airlaid pulpnonwovens and the absorbent cores of products, such as diapers, sanitarynapkins and adult incontinence pads.

Yield: The number of square meters (square yards) produced by a kilogram(pound) of fiber or resin.