nonwovens - presentation
TRANSCRIPT
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