Chapter 4 Production of Manufactured Fibers

70% of all textiles usedApparel – 48%

Home furnishings – 40%excluding floor coverings

Floor coverings – 99%Industry – 91%

Characteristics of Manufactured Fibers

Quantities can be controlled easily b/cnot dependent on nature

Properties may be tailored to the needs of the consumerBlending of manufactured fibers◦ With natural fibers - optimize end product

characteristicsEx. polyester/cotton blend:

cotton gives comfort and pleasant handpolyester adds resilience and durability

Categories of Manufactured Fibers

Three main categories◦ Manufactured Cellulosics

Derived from wood pulp and cotton lintersCannot be used as textiles in their original form

◦ SyntheticsCreated from petrochemicals

◦ Inorganic fibersGlassMetalCeramic

Generations of Manufactured Fibers

First generation ◦ Regenerated from natural materials

Rayon

Second generation ◦ Synthesized from petroleum products

Nylon

Third generation◦ Developed within the past 20 years ◦ High-performance or high technology

Microfibers

Formation of Manufactured Fibers

Spinning◦ Process of making a manufactured fiber

Polymer (fiber forming substance) gets melted into dopeDope is extruded/forced through a Spinneret

◦ SpinneretLooks like a showerheadHas multiple holes, each one creates one filament

Antron® nylon solution dyed polymer chips

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Spinneret

Filament Fiber Production

Filaments extruded simultaneouslyEach filament does not touch each otherFilaments are hardened as they emerge from the Spinneret Several techniques for hardening the filaments

Described by the number and size of the filaments◦ 70/40

Yarn is 70 denier and there are 40 filaments

Hardening Techniques for Filament Fibers

Melt spinning◦ Polymer melted◦ Force thru Cool air to

solidify◦ Simple / less expensive

Nylon, olefin, polyester, saran and glass

Hardening Techniques for Filament Fibers

Dry spinning◦ Polymer dissolved in

solvent◦ Extruded into warm, dry

air◦ Warm air dissolves the

solvent + hardens the filament◦ Acetate, vinyon, some

acrylics

Hardening Techniques for Filament Fibers

Wet spinning◦ Polymers dissolve in chemical bath◦ Extruded into other chemical bath◦ Acrylic and viscose rayon

Hardening Techniques for Filament Fibers

Solvent spinning◦ Newest process◦ Polymer is dissolved in amine oxide◦ Extruded into solvent bath◦ Tencel, Lyocell

Special-Use Spinning Methods

Gel Spinning◦ Hybrid of wet + dry spinning◦ Also called Solution Spinning◦ Plastic films and packing materials◦ Spectra®

Emulsion Spinning◦ for insoluable fibers – high melting points◦ Teflon®◦ GORE-TEX® fabrics

Specialized Fiber FormationHeterogeneous fibers◦ Bicomponent

Hollow fibers

Microfibers

Fibrillated fibers

Advantages of Bicomponent Fibers

Single fiber has characteristics of both polymers

◦ Increased comfort◦ Better absorbency◦ Cross-dyed effects can be achieved

Bilateral FibersAlso called side-by-side bicomponent fibers◦ Two different polymers fed into spinneret

Fig 4-4a p.58

◦ Benefit of crimpResult of one fiber shrinking more than the other Crimped fibers have:

Improved handIncreased coverLoft elasticity

Sheath-Core Fibers

Spun so one fiber encases the other

◦ See #43 on p.26 of your Swatch Kit

◦ Refer to Fig 4-4b on p. 58 of textbook

Matrix or Biconstitute Fibers

Created with two generically different fibers◦ Fine, short lengths of one fiber embedded in

another before extrusion Fig. 4-5

Hollow FibersHave one or more spaces in their centers Fig 4-6 p. 58◦ Air injected into fiber as it is being formed◦ Shape determined by spinneret holes◦ By adding gas producing compounds to the spinning

solution

Lightweight and trap air◦ Often used for cold weather clothing

Thermolite® by DuPont

Photomicrograph of hollow nylon fibers (cross section)

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Photomicrograph of hollow nylon fibers (cross section)

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ITS Intertek Testing ServicesLabtest

MicrofibersProduced by carefully controlled melt spinning

◦ Splitting methodTwo incompatible polymers are extruded then separated.

◦ Sea-island methodPolymer for the microfiber is embedded into another polymer.

Also called microdenier fibersCharacteristics◦ Soft◦ Excellent drape

Fibrillated fibers◦ Characteristics

Coarse fibers used for bagging and twine◦ Extrude asheet of polymer◦ Draw and stretch the sheet

This causes it to break into interconnected fibers

Manufactured Fiber ModificationsDictated by the Projected End Use

Drawing

Heat setting

Texturing

Cutting

Modifications continued

Drawing –parallel alignment or orientation of molecules

Partially oriented yarns (POY)◦ Not drawing to the maximum length

Fully oriented yarns (FOY)◦ Drawing to the maximum length

Undrawn Antron® nylon fiber

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Modifications continued

Heat Setting◦ Heat and pressure permanently change shape

Improves dimensional stability of thermoplastic yarns

.Create permanent pleats and creases

Pleats Heat Set into Polyester

Modifications continued

Texturing – Produces the following:◦ Bulkier yarns◦ Opaque yarns◦ Yarns with elastomeric qualities

Since synthetic fibers are moldable, they will retain a permanently textured shape

Modifications continued

Cutting◦ Creates staple yarns from filament fibers

◦ Extruded from spinnerets with many holes to produce more economically

◦ See Fig. 4 – 8 p. 61 for a detailed summary of the process

Antron® nylon staple tow

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Additional Treatments

Applied during the spinning process◦ Additives such as:

DyesPigmentsDelusterantsWhiteners

Chapter 5 Manufactured Cellulosic Fibers

Two categoriesRegenerated cellulosic fibers

Derivative cellulosic fibers

Both made from cotton linters and wood pulp

Regenerated Cellulosic Fibers

Rayon◦ Pure cellulose fiber◦ Originally produced from mulberry trees◦ Known as “artificial silk”◦ Viscose rayon only type produced in US

Viscose rayon fiber

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Varieties of Rayon

Originally inexpensive to manufacture

Viscose RayonCuperammonium rayonHigh-wet modulus (HWM) or polynosic rayonHigh-tenacity rayon

General Properties of Rayon

Excellent absorbencyWet strength lower than cottonPoor resiliencyDoes not pill

Photomicrograph of viscose rayon fibers

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Photomicrograph of flat rayon fibers (cross section)

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Mechanical Properties of Viscose Rayon

Medium-weight fiberNot as strong as cottonAbrades more easily than cottonWeaker wet than dryNot dimensionally stable◦ Tends to shrink progressively when launderedPoor elastic recoveryPoor resilienceFlexible fiber

Chemical Properties of Viscose Rayon

Very absorbentComfortable to wearDyes readily in rich vibrant colors

Burns like cottonConducts electricity – no static buildup◦ Catches fire when exposed to open flame.◦ Continues to burn when flame is removed.◦ Smells like burning paperAcids and alkalis degrade it

Environmental Properties of Viscose Rayon

Silverfish

Mildew

Sunlight

End Uses of Viscose RayonFrequently used in blends◦ Blended with fibers that are more durableMost rayon fabrics are woven

Fiber may stretch when damp or wet

Nonwoven rayon fabric used in medical and sanitary products

Care of Viscose Rayon

Dry cleaning recommendedNonchlorine bleaches are safeFollow care labels!!! Store in a clean, dry environment

More Rayon p.67

Cuperammonium Rayon◦ Bemberg rayon (bember industries until 1975)◦ Known as cupro◦ Silkier in feel and appearance◦ Lightweight summer clothing

More Rayon

High-Wet Modulus Rayon◦ Stronger, more resilient, more dimensionally stable◦ Modulus refers to resistance to stress + strain◦ European generic name is Model

High-tenacity Rayon◦ stronger than viscose

LyocellNewest regenerated cellulosic fiber◦ Tencel® by Courtaulds Fibers, Inc.◦ Lenzing Lyocell® by Lenzing Fibers

CorporationSolvent used is nontoxic◦ Self-contained solvent-spun process

Creates little water and air pollution◦ Environmentally friendly fiberProcess more expensive

Tencel® lyocell fiber

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Physical Properties of Lyocell

Fiber is roundSmoothNo striationsFibrils or tiny fibers on surface◦ Creates a fine, soft finish with reduced luster

Photomicrograph of lyocell fibers

ITS Intertek Testing ServicesLabtest

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Mechanical Properties of Lyocell

Stronger than other cellulosic fibers

More abrasion resistance

Less shrinkage

Better resilience

Chemical Properties of Lyocell

Similar to rayonAbsorbentDyes wellComfortable to wearExcellent static resistance

Environmental Properties of Lyocell

Similar to rayon◦ Silverfish

◦ Mildew

◦ Sunlight

End Uses of LyocellApparel & Home Furnishings

Knits and Wovens

Due to high cost – limited nonwoven applications

Frequently used in blends◦ Especially cotton

Care of Lyocell

Wash or Dry clean

Follow care labels closely

Friction can cause additional fibrillation of fibers

Derivative Cellulosic Fibers

Acetate and Triacetate◦ Chemically changed during production

◦ Derivative of cellulose called estersFIBERS ARE NOT CELLULOSE

Cellulose Acetate Commonly Called Acetate

Developed during WW1 as coating for aircraft wingsAfter war it was developed into a fiberProduction began in 1924First thermoplastic fiberTrade names◦ Chromespun®◦ Estron®

Physical Properties of Acetate

White fiberLongitudinal striationsIrregular cross section resembling popcorn – see p. 70Lustrous, but may be delusteredSmooth handWhite unless dyed prior to extrusion

Photomicrograph of acetate fibers

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Mechanical Properties of Acetate

Very weak fiberLighter in weight than cotton or rayonPoor abrasion resistancePoor elasticityPoor resilienceNot dimensionally stableDoes not pillDrapes well

Chemical Properties of AcetateModerate absorbencyBuilds static electricityMelts at temps over 275ThermoplasticResistant to acids and basesCan be bleached with nonchlorine bleachNot as comfortable to wear as:◦ Cotton, linen or rayon

Environmental Properties of Acetate

Susceptible to atmospheric gases◦ Color may change

Silverfish if heavily starchedMildewSunlight degrades◦ But less than silk/other cellulosic fibers◦ Delustered acetate less resistant to sunlight

End Uses of AcetateApparel and Home FurnishingsDon’t use when durability is neededLining fabricFrequently used in:◦ Taffeta, satin and brocade for formal wearCigarette filtersPersonal hygiene productsFiberfillFilters

Care of Acetate

Dry cleaning recommended

Stay away from acetone

Nonchlorine bleaches may be used

Triacetate

U.S. production ceased in 1986Produced today in;◦ United Kingdom◦ Japan◦ Belgium

Similar to acetate:◦ Physical and chemical properties◦ Differs mechanically

Triacetate

Mechanical Properties (compared to acetate)

◦ Better resiliency◦ Better dimensional stability◦ Better elasticity◦ Like acetate

Low strengthPoor abrasion resistance

TriacetateChemical Properties (compared to acetate)

◦ Less absorbant

◦ Builds up static electricity (like acetate)

◦ Much less senstitive to acetone

◦ Less heat-sensitive (given special heat setting treatment)creases and pleats are more permanent

Environmental Properties◦ More resistant to mildew than acetate

◦ Resistant to silverfish, moths and carpet beetles

◦ Moderate resistant to sunlight

TriacetateEnd Uses◦ Used when durability is not important

◦ Used when pleat and crease retention is important

◦ Bedspreads

◦ Comforters

◦ draperies

TriacetateCare of◦ Machines washed

◦ Hand washed

◦ Dry cleaned

◦ Use non-chlorine bleach

◦ Needs lining for sunlight if used as draperies

◦ Acetone will damage it.

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