nonwovens - presentation

World of Nonwovens

A Presentation by

Dr. V. K. KothariProfessor

Textile Technology DepartmentIndian Institute of Technology Delhi

At NIT Jalandhar 6 March 2010

What are Nonwovens?What are Nonwovens?

• Nonwovens are engineered fabrics

•Nonwovens are manufactured by high speed low cost processes- large volume, lower cost than traditional processes

•Nonwovens are produced by a variety of processes with a wide range of properties

•Nonwovens are in many applications already, but most are hidden and you do not see them

INDA Definition

Nonwovens are a sheet, web, or batt of natural and/or man-made fibers or filaments, excluding paper, that have not been converted into yarns, and that are bonded to each other by any of several means.

The various methods for bonding are:a) Adding an adhesiveb) Thermally fusing the fibers or filaments to each other or to the other meltable fibers or powders.c) Fusing fibers by first dissolving, and then resolidifying their surfaces.d) Creating physical tangles or tuft among the fibers.e) Stitching the fibers or filaments in place.

EDANA Definition

Nonwovens are a manufactured sheet, web or batt of directionally or randomly oriented fibers, bonded by friction, and/or cohesion and/or adhesion, excluding paper or products which are woven, knitted, tufted stitchbonded incorporating binding yarns or filaments, or felted by wetmilling, whether or not additionally needled.

The fibres may be of natural or man-made origin. They may be staple or continuous or be formed in situ.

Nonwoven ProductsNonwoven Products

Today’s nonwovens are highly engineered solutions made up of a variety of materials including fibres, powders, particles, adhesives, films and other materials that provide specific solution or solutions by providing a multitude of functionalities.

Hospital SuppliesHospital SuppliesHygiene applicationsHygiene applicationsConsumer productsConsumer productsInterliningsInterliningsGeotextilesGeotextilesCarpet BackingsCarpet BackingsAutomotive PartsAutomotive PartsFiltersFiltersWipesWipes… …

Charting the Path Forward

Products That Use Nonwovens

AgricultureCrop Covers

Turf protection products

Weed control fabrics

Root bags

Containers

Capillary matting

AutomotiveTrunk liners

Carpet backing

Door trim panel carpeting

Door trim panel padding

Wheelhouse covers

Rear shelf trim

Seat applications

Headliners

Cover slip sheets

Foam reinforcements

Oil, fuel, air & other filters

Vinyl, landau cover backings

Sound, heat insulation

Home FurnishingsFurniture construction fabrics:

Insulators, arms and backs

Cushion ticking

Dust covers

Decking

Skirt linings

Pull strips

Bedding construction fabrics:

Quilt backings

Dust covers

Flanging

Spring wrap

Spring insulators

Blankets

Wallcovering backings

Acoustical wallcoverings

Upholstery backings

Pillows, pillowcases

Window treatments

Drapery components

Carpet backings

Carpeting

Mattress pad components

Industrial/MilitaryCoated fabrics

Filters

Semiconductor polishing pads

Wipers

Clean room apparel

HVAC filters

Military clothing

Abrasives

Cable insulation

Reinforced plastics

Tapes

Protective clothing, lab coats

Sorbents

Lubricating pads

Flame barriers

Packaging

Conveyor belts

Display felts

Papermaker felts

Noise absorbent felts

Charting the Path Forward

Products That Use Nonwovens…..continued

School, OfficeBook covers

Mailing envelopes, labels

Floppy disk liners

Towels

Pen nibs

ClothingInterlinings

Clothing and glove insulation

Bra and shoulder padding

Handbag components

Shoe components

HealthcareSurgical: caps, gowns, masks, shoe covers

Sponges, dressings, wipes

Orthopedic padding

Bandages, tapes

Dental bibs

Drapes, wraps, packs

Sterile packaging

Bed linen, underpads

Transdermal drug delivery

Contamination control gowns

Electrode pads

Examination gowns

Filters for IV solutions, blood oxygenators & kidney dialyzers

GeotextilesAsphalt overlay

Road and railroad beds underlay

Soil stabilization

Drainage

Dam and stream embankments

Artificial turf

Sedimentation & erosion control

Pond liners

HouseholdWipes, wet, dry, polishing

Filters

Vacuum cleaner bags

Scouring pads

Fabric softener sheets

Dust cloths, mops

Place mats, napkins, table clothes

Ironing board pads

Washcloths

Leisure, TravelSleeping bags

Tarpaulins, tents

Artificial leather, luggage

Airline headrests, pillow cases

Personal CareBaby diapers

Feminine care, tampons

Tea, coffee bags

Toddler training pants

Incontinence products

Dry and wet wipes

Cosmetic applicators, removers

Lens cleaning tissues

Hand warmers

Buff pads

ConstructionInsulation

Roofing and tile underlay

Acoustical ceilings

House wrap

Pipe wrap

Nonwoven ProductsNonwoven Products

Web Formation

The dry-laid processWeb is produced from staplefibers Production takes placein a carding machine fitted withrotating rollers.

The wet-laid processThe fibers are separated by waterand laid on a circulating screenbelt on which the water isdrained off.

Web Formation

The spunbonding processThis is a continuous productionprocess, from raw material(granulate) to web. The webrequires boding.

The meltblowing processThis is a continuous productionprocess, from raw material(granulate) to web. The webRequires no bonding.

Web Formation

The pulp-based airlay processThis is a continuous productionprocess, from small fibers – pulpand powders to web.

The Rando airlay processThis is a continuous productionprocess, from staple fibers andalmost anything else to web.

Web BondingWeb Bonding

Adhesive bondingHere the fibers arebonded by means ofan adhesive.

NeedlingHere the fibers arebonded using needleswith barbs.

Thermal bondingThis is homogenousbonding of the fibersbetween hot, rotatingcylinders.

HydroentanglingThis is mechanicalbonding by means ofultrafine, powerful jetsof water.

Nonwoven Fabrics

How do we make nonwovens?How do we make nonwovens?

From Fibres:

Web Forming Dry-lay (Carding) Air-lay Wet-lay

Bonding Mechanical - Needling - Hydroentangling Thermal - Calendering - Thru-air Chemical Adhesive

From Polymers:

Extrusion & Web Forming• Spunbond• Meltblown

Bonding• Mechanical

- Hydroentangling• Thermal

- Calendering- Thru-air

Production of Nonwovens

• Two major steps in the manufacture of nonwovens:

– web formation – bonding of fibers in the web

CARDED Air-laid Web

• The most effective way of minimizing fiber alignment• Sweeps the opened fibers from a wire- wound roll

(either card or opening system) into a stream of air, and then condenses the fiber on a slowly moving screen or perforated drum

• Normal cards may be modified in-house in yarn manufacturing operations to allow the production of a marketable product from manufacturing waste

• Commercial machine manufacturers:

Rando Machine Co., D.O.A., and Fehrer

Air-lay Process

Rando-webber

Spunbond Process

• Uses air as dispersing medium for continuous filament fibers

• Is a single operation (fiber manufacturing and web formation processes are linked )

• Nonwoven batt is produced by falling through the air and by landing on a moving conveyor of continuous filament fibers

• Requires a large number of filaments (from multiple spinnerettes) to produce a web of reasonable width

Spunbond (continued)

• Is a random dispersion of the filaments (desirably)

• Electrostatics may be used to keep the filaments separated and dispersed in the web

• Bonding of the fibers (thermal-bonding or needle punching) is done in line before take-up of the batt

Spunbond Process

Reicofil Spunbond Process

Multiple spunbond layers

Spunbonding Process

• Integrated process

• Production rate: 30 to 300 m2 /min.

• Filament production speed: 1000-6000 m/min being operated.

• Isotactic polypropylene has been used predominantly in commercial production.

• Other Polymers Used- Polyesters, Nylons PE and Bicomponents

Spunbonded Fabrics

• Random fibrous structure• Basis weights range between 5 and 800 g/m2,

typically 10-100 g/ m2• Web thickness range between 0. 1 and 4.0 mm,

typically 0.2-1.5mm• Fiber diameters range between 1 and 50 um, but the

preferred range is between 15 and 30 um • High strength-to-weight ratios compared to other

nonwoven, woven, and knitted structures• High tear strength

Spunbonding Process Variables

• Spinning• Melt Temperature

• Throughput

• Quench Air Temp

• Draw Down Speed

• Laydown• Spinning Speed/Belt

Speed

• Bonding• Type

• Bond Area

• Temperature

• Time (Speed)

• Pressure

Melt Blowing Process• Is similar to spunbonding, but fabric has much

better barrier and lower strength• Uses a high-velocity stream of air to force the

filaments away from the spinneret face• Fibers are attenuated by air-stream to a degree of

fineness much smaller than typical extruded textile fibers

• Fibers (typically 1-5 microns) are deposited onto a condenser/conveyer belt and bonded before take-up

• Makes a web with very fine pore-structure and large surface area

• Suitable for absorption and filtration applications

Melt Blowing Process

Wet-laid Process

• Water is used to deposit a fibrous web onto a condenser screen

• Similar concept of papermaking process

– by suspending fibers in water, and then draining the suspension through a condensing screen

Wet -lay Process

Fiber Length for Wet-lay Process

• Need less than 1/4 inch (normal textile process > 1inch)• Long fibers (1/2 to 1 inch)

– need very high dilution ratio• Longer than 1 inch

– is impractical on ordinary paper machines

Wet-laid Fabrics

• Are made of a variety of saturation substrates

• Glass fiber or mixtures of wood pulp and other fibers

• Absorbent wiping materials

• Glass fiber mats for roofing products

Fiber Bonding

• Fibers in a batt without interlacing - the batt has little strength• Fiber bonding is necessary to develop strength in a batt:

– Needle punching– Hydroentanglement– Adhesive application– The fiber may be its own adhesive

Needlepunching Process

• Barbs on needles catch fibers on the surface of the batt, push them into the center, densify structure and produce strength through entanglement

• a bed plate supports the web and a stripper plate strips the fabric off the needles as they are withdrawn

– needling can be done from both sides of the fabric

– penetration of needles does not have to be perpendicular to the sheet structure

Needlepunching

Needles

Hydroentanglement Process

• Employs fine jets of water to push fibers from the surface toward the interior of the fabric

• An apertured fabric is produced by more powerful jet and an appropriate backing screen

• Less forceful jets produce entanglement without completely penetrating the fabric

• Batt must be supported when struck by water stream

• Water stream does not exert as great a force on fibers as that of needlepunching

Hydroentanglement

• The size, spacing, and height of the knuckles on the conveyor or plate surface have a major influence on ability of the fibers to entangle, and the appearance of the fabric

• Less dense and more flexible than those produced by needlepunching

• Referred to as spunlaced fabric

• Can be used to bond relatively thin fabrics

Hydroentanglement

Hydroentanglement Jets

Hydroetanglement wire

Hydroentanglement wire

Hydroentanglement wire

Adhesives

• Provide structural integrity to nonwovens• Bind the fiber together• Are included as either a secondary treatment, or in the

form of adhesive-containing fibers • Solid form (powders or fibers): in the finished fabric• Liquid form: in the batt

(melts, solution emulsions, suspensions, pastes and foams)

• The form determines the process used for application

Application of Liquid Adhesives

• Spraying

• Dipping and squeezing

• Printing (kiss-rolls, screen, gravure)

• Foam application

Spray bonding

Thermal Bonding

• Thermoplastic materials are activated by either convective, conductive, or radiant heating

• An engraved roll provides point bonding, while a smooth roll tends to bond the entire area

• Hot air forced through the fabric (convection) to melt adhesive without producing excessive compression

• Infra-red heating (radiant) minimizes compression. Works best on relatively thin or low-density materials

• Ultrasonic energy can also be used to fuse materials, usually in a point bonded pattern

Through-air Thermal Bonding

Through air bonding

Calendar Bonding

Engraved rolls

Nonwoven Fabrics

Nonwoven Fabric Manufacturing Options

Fiber Selection

Abaca PBI Acetate PBT Acrylic PEAramid PEN Coir PETElastomer PLA Flax PP Glass PTT Hemp pulp Jute rayonLyocell sulfarMelamine triacetate Metallic urethaneModacrylic vinyonNylon wool

Cotton

Web Formation

Carding parallelscrambled random

Crosslap Airlay Wetlay Spunbond

Meltblown Film Net

Bonding

Needlepunch Hydroentangle StitchbondSpray Saturate Print FoamCalender ThruairUltrasonic

Finishing

Hydrophilic Hydrophobic Repellent Flame Retard Coating Antimicrobial Dye Print Corrugate Emboss Compact Crepe Flock Plasma Encapsulate

At What Speeds?At What Speeds?

SpunMelt> 300-1000 metres per minute – 5 to 6 metres wide

High Speed Cards> 300-400 metres per minute – 5 to 6 metres wide

Other processes have to become compatible for these Other processes have to become compatible for these to work. These include winding, bonding, etc…to work. These include winding, bonding, etc…

Auto Air Filteration Auto Air Filteration

• micronAir particle filters,with their higharrestanceMicrofiber nonwovens, protectdriver and passengers of avehicle from pollen, dust, soot and other harmful particlespenetrating inside theircar via the intake airflow.

• Nonwovens for filteringcoolants and lubricants, aswell as washing, phosphatingand coagulation baths in themetal-processing industry.

Liquid FiltrationLiquid Filtration

• Nonwovens for filtering milk,frying fats, drinking water,and blood plasma.

• Membrane supportnonwovens for filtering fruitjuices, enzymes, electro-dip-coatingand effluents.

Indoor Climate Control and Air Indoor Climate Control and Air Filtration Filtration

Air filters for intake, exhaustand recirculated air filtrationin indoor climate controlsystems:

filter mats pocket filters activated-carbon combination filters cassette filters HEPA/ULPA filters depth-loading filter cartridges high-temperature filters

Dust RemovalDust Removal

Filter cartridges, filterplates, filter bags andEcoProtec safety filtersfor industrial dustremoval applications,with high-performancefilter media made ofnonwovens.

Special FiltrationSpecial Filtration

• Respirators • Vacuum cleaners • Kitchen hood filters • …

HygieneHygiene

Baby diapers

Incontinence products

Feminine hygiene items

MedicalMedical

In medical applications,nonwovens offer maximizedlevels of safety and hygiene.They are used in adhesiveplasters, wound pads andcompresses, orthopedicwaddings and stomaproducts.

The nonwovens used heremust, for example, beparticularly absorbent andair-permeable, must not stickto the wound, and also haveto ensure a skin-friendlymicro-climate.

Furniture/Textile ApplicationsFurniture/Textile Applications

• In furniture/textileapplications, nonwovenssatisfy even the mostdisparate functionalrequirements for producingupholstered furniture,bedware and quiltedproducts, and protectiveclothing.

• Nonwovens here excel interms of their textile look,their air-permeablebreathability, and highabrasion resistance values.

HorticultureHorticulture

In horticulturalapplications, nonwovensprotect the plantsagainst temperatureextremes by day and bynight, thus creating thefoundation for earlierharvests with excellentresults. They arepermeable to both airand water, UV-stabilized,and resistant to rotting.

Nonwovens for CablesNonwovens for Cables

Nonwovens for cablebandaging are used in powerand telecommunicationcables. Nonwovens help tokeep the cable fully functionalon a long-term basis evenunder the toughest ofconditions.

Nonwovens act as Water-blocking tapes, as fixing, bedding and thermo-tapes, and in an electricallyconductive versions for Heat-barrier protection.

Acoustic NonwovensAcoustic Nonwovens

o Optimized noise dampingranks among the mostimportant requirements forthe architects and engineersdesigning modern-day offices,administration buildings,airports and communicationcenters.

o The structure and low weightof acoustic nonwovens offer asignificant advantage inperforated ceiling systemscompared to conventionalsoundproofing materials.

Composite MaterialsComposite Materials

In the glass-fiber-reinforcedplastic industry, nonwovensare used for surfacingproducts like pipes, tanks,container boards, facadepanels, skis, surfboards andboats. They very substantiallyimprove resistance to bothcorrosion and abrasion, aswell as improving themechanical strength of theproducts.

Polishing PadsPolishing Pads

Polishing pads are used in themanufacture of semiconductor wafers, memory discs, precisionoptics and metallurgicalcomponents.

The purpose of these pads isto produce a surface finish, interms of planar uniformityand smoothness, that canmeet the highest tolerances.

Automotive InteriorsAutomotive Interiors

Facings and structuralreinforcement materialsare used in a variety ofdifferent applicationsIncludes:

headliners,

trunkliners,

door trim,

package trays,

sun visors and

seats.

Window TreatmentsWindow Treatments

► Nonwovens are used indesigner window treatmentfabrics to enhance bothfunction and appearance. ► Their ability to diffuse light,while maintaining roombrightness, enhances thefeeling of privacy and helpsprotect furniture. ► Their natural insulatingqualities provide addedenergy conservation.

A broad spectrum of

applications including:

- liners, - counterliners, - interliners and - reinforcing materials

In In Shoes..Shoes..

Membranes and insolesensure a healthy footclimate and a highdegree of foot comfort.

Nonwovens perform

excellently as substratefor coagulates andcoated materials.

Appropriately finishedmaterials are used notonly in shoe andleather goods but also inupholstery and even inthe garment industry.

As As SubstratesSubstrates

Tufted CarpetsTufted Carpets

In Carpets, nonwovensconstitute the invisiblesupporting inside layerof tufted carpets andcarpet tiles.

In automotive carpets,nonwovens are used asfirst and secondbackings mainly formaking moldedautomobile carpets.

Major TrendsMajor Trends

o Materials- Permanently Hydrophilic Polypropylene/Polyesters - New sustainable materials – PLA, Bio PET, Kenaf - Bicomponent Staple Fibers

o Processes • Innovative SpunMelt

- Bicomponent meltblown/spunbond products• High speed/high volume processing – Carding • New Innovative/Combined processes – Coform o Post-Processes • Surface treatments • Coatings/laminations o Product Innovations • Composites • Coforms

Functionalizing SurfacesFunctionalizing Surfaces

Topical Finishes• staple fibers ( typically done by fiber producer) • SpunMelt fabrics

- require an added step in the process

Surface Modifications

• Atmospheric Plasma

• Cold Plasma

• Electron Beam

Increased Surface Area

• Smaller Fibres – Micro and Nano fibres

Melt Additives • Staple fibers • SpunMelt fabrics

Enabling TechnologiesEnabling Technologies

The major innovations in products will be based on:

Materials • New innovative (sustainable) materials • Bicomponent/multi-component fiber technologies

Processes

• New innovative processes – Apex, • Co-forms

Products

• Composites

Why Bicomponent Fibers?Why Bicomponent Fibers?

♦ To utilize the properties of two polymers

♦ To exploit capabilities not existing in each of the individual polymers

♦ To improve the material performance suitable for specific needs by tailoring one or more properties with minimal sacrifice of other properties

♦ To bring about multifunctional propertieswithout the loss of mechanical properties

ClassificationClassification

Side-by-side

Sheath-core

Segmented-pie

Islands-in-the-sea

Tipped

Segmented-ribbon

Segment-Pie: Splitting by CardingSegment-Pie: Splitting by Carding

Card-splittable fiber before splitting Card-splittable fiber after carding

Increased Surface AreaIncreased Surface Area

Evolon is anewly patented,award winning method formanufacturing

Evolon… The Next GenerationEvolon… The Next Generation

Evolon… The TechnologyEvolon… The Technology

16 Sector PIE ~ 0.1 dtex

2 Sector S/S ~ 1 dtex

Increased Surface Area: How About Nano Increased Surface Area: How About Nano Fibers?Fibers?

Electrospinning

• 10 to 200 nm

Meltblowing

• 500 nm to 10 μm

Bicomponent Fibres

• 200 nm to 1000 nm

Bicomponent Fibres in Spunbonding

Bicomponent Fibres in Meltblowing

300 Islands-in-the-sea As-spun Fiber300 Islands-in-the-sea As-spun Fiber

2000 Islands-in-the-sea As-spun Fiber2000 Islands-in-the-sea As-spun Fiber

Engineering the Product Engineering the Product Composites Composites

Composite Nonwovens (CN) are made:

from 2 or more fibers

• Homogeneous blends and gradients

• Layered structures

from fibers and particulates from 2 or more layers with at least one being a nonwoven

Why Composites?Why Composites?

Economical solution:Economical solution:

• Eliminate stepsEliminate steps

• One product replaces two or moreOne product replaces two or more Best technical solution –Engineered solutionBest technical solution –Engineered solution Profit improvementProfit improvement

• Specialized solutionSpecialized solution

Composite Nonwovens Made From Fibers & Composite Nonwovens Made From Fibers & Filaments: ExamplesFilaments: Examples

Thinsulate® from 3Mcomposed of large fibers+sub-denier fibers Synthetic leathercomposed of Spunlacedsplittable fibers

Layered CompositesLayered Composites

Processes with more than one forming sectionadding different fibers or filament to a web.Examples are:

• multi-card process,

• multi-forming box air-laid process,

• multi-beam spunbond process,

• combinations of various forming

processes like SMS

Composites Made by LaminationComposites Made by Lamination

Lamination are made by thermal bonding,ultrasonic bonding, adhesive bonding,extrusion coating, needling and spunlacing.The laminates are:

made up from two or more layers of nonwovens or

made up from at least one nonwoven and at least one different layer (film, reinforcement net, etc…)

Spunbond + Spunlace – Spunbond + Spunlace – Hydroknit® ( KC)Hydroknit® ( KC)

Coform – A Great ExampleCoform – A Great Example

Layered Composites: Layered Composites: ExamplesExamples

Spunlaced fabrics made of wood pulp and Synthetic Fibres

• Tissues paper layered ontop of carded web prior tohydroentanglement • Fabric has one side rich inwood pulp fiber • Treatment is added towood pulp fibers toachieve barrier properties

Nonwovens whereparticulates are bondedto the fiber or filamentwith an adhesive ( e.g.Abrasive pad whereabrasive particulates arebonded to the fibers withA latex. Same approachhas been used forcarbon black)

Composite Nonwovens With Composite Nonwovens With ParticulatesParticulates

Composite Nonwovens With ParticulatesComposite Nonwovens With Particulates

Nonwovens made up of bicomponent fibers,where the outer layer ismelted to form bondsbetween the fibers andbetween the fibers andthe particulates.

Thank YouThank You