Production of manufactured fibers

Characteristics of Manufactured Fibersy Quantities can be controlled easily b/c not dependent on nature y Properties may be tailored to the needs of the consumer y Blending of manufactu

Chapter 4 Production of Manufactured Fibers

70% of all textiles used

Characteristics of Manufactured Fibers

y Quantities can be controlled easily b/c

not dependent on nature

y Properties may be tailored to the needs

of the consumer

y Blending of manufactured fibers

◦ With natural fibers - optimize end product characteristics

Ex polyester/cotton blend:

cotton gives comfort and pleasant hand polyester adds resilience and durability

Categories of Manufactured Fibers

y Three main categories

◦ Manufactured Cellulosics

x Derived from wood pulp and cotton linters

x Cannot be used as textiles in their original form

Generations of Manufactured Fibers

◦ Developed within the past 20 years

◦ High-performance or high technology

x Microfibers

Formation of Manufactured Fibers

y Spinning

◦ Process of making a manufactured fiber

x Polymer (fiber forming substance) gets melted into dope

x Dope is extruded/forced through a Spinneret

◦ Spinneret

x Looks like a showerhead

x Has multiple holes, each one creates one filament

Antron® nylon solution dyed

polymer chips

6

Spinneret

Filament Fiber Production

Filaments extruded simultaneously

y Each filament does not touch each other

y Filaments are hardened as they emerge from the

Spinneret

y Several techniques for hardening the filaments

y Described by the number and size of the filaments

◦ 70/40

x Yarn is 70 denier and there are 40 filaments

Hardening Techniques for Filament Fibers

y Melt spinning

◦ Polymer melted

◦ Force thru Cool air to

solidify

◦ Simple / less expensive

Nylon, olefin, polyester, saran and glass

Hardening Techniques for Filament Fibers

◦ Warm air dissolves the

solvent + hardens the

filament

◦ Acetate, vinyon, some

acrylics

Hardening Techniques for Filament Fibers

y Wet spinning

◦ Polymers dissolve in chemical bath

◦ Extruded into other chemical bath

◦ Acrylic and viscose rayon

Hardening Techniques for Filament Fibers

y Solvent spinning

◦ Newest process

◦ Polymer is dissolved in amine oxide

◦ Extruded into solvent bath

◦ Tencel, Lyocell

Special-Use Spinning Methods

y Gel Spinning

◦ Hybrid of wet + dry spinning

◦ Also called Solution Spinning

◦ Plastic films and packing materials

Specialized Fiber Formation

Advantages of Bicomponent Fibers

y Single fiber has characteristics of both polymers

◦ Increased comfort

◦ Better absorbency

◦ Cross-dyed effects can be achieved

Bilateral Fibers

y Also called side-by-side bicomponent fibers

◦ Two different polymers fed into spinneret

x Fig 4-4a p.58

◦ Benefit of crimp

x Result of one fiber shrinking more than the other

x Crimped fibers have:

x Improved hand

x Increased cover

x Loft

x elasticity

Sheath-Core Fibers

y 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

y Created with two generically different fibers

◦ Fine, short lengths of one fiber embedded in another before extrusion Fig 4-5

Hollow Fibers

y Have 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

y Lightweight and trap air

◦ Often used for cold weather clothing

x Thermolite® by DuPont

Photomicrograph of hollow nylon

fibers (cross section)

21

ITS Intertek Testing ServicesLabtest

Photomicrograph of hollow nylon

fibers (cross section)

22

ITS Intertek Testing ServicesLabtest

Fibrillated fibers

◦ Characteristics

x Coarse fibers used for bagging and twine

◦ Extrude asheet of polymer

◦ Draw and stretch the sheet

x This causes it to break into interconnected fibers

Manufactured Fiber Modifications Dictated by the Projected End Use

y Drawing

y Heat setting

y Texturing

y Cutting

Modifications continued

orientation of molecules

y Partially oriented yarns (POY)

◦ Not drawing to the maximum length

y Fully oriented yarns (FOY)

◦ Drawing to the maximum length

Undrawn Antron®

nylon fiber

27

Modifications continued

◦ Heat and pressure permanently change shape

x Improves dimensional stability of thermoplastic yarns

.

x Create permanent pleats and creases

Pleats Heat Set into Polyester

Modifications continued

◦ Bulkier yarns

◦ Opaque yarns

◦ Yarns with elastomeric qualities

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

Modifications continued

◦ 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

32

Additional Treatments

y Applied during the spinning process

◦ Additives such as:

x Dyes

x Pigments

x Delusterants

x Whiteners

Chapter 5 Manufactured

Cellulosic Fibers

Two categories

Regenerated cellulosic fibers

Derivative cellulosic fibers

Both made from cotton linters and wood pulp

Regenerated Cellulosic Fibers

y Rayon

◦ Pure cellulose fiber

◦ Originally produced from mulberry trees

◦ Known as “artificial silk”

◦ Viscose rayon only type produced in US

Viscose rayon fiber

36

General Properties of Rayon

Photomicrograph of

viscose rayon fibers

ITS Intertek Testing ServicesLabtest

39

Photomicrograph of flat rayon fibers

(cross section)

ITS Intertek Testing ServicesLabtest

40

Mechanical Properties of

Viscose Rayon

y Medium-weight fiber

y Not as strong as cotton

y Abrades more easily than cotton

y Weaker wet than dry

y Not dimensionally stable

◦ Tends to shrink progressively when laundered

y Poor elastic recovery

y Poor resilience

y Flexible fiber

Chemical Properties of

Viscose Rayon

y Very absorbent

x Comfortable to wear

x Dyes readily in rich vibrant colors

y Burns like cotton

y Conducts electricity – no static buildup

◦ Catches fire when exposed to open flame.

◦ Continues to burn when flame is removed.

◦ Smells like burning paper

y Acids and alkalis degrade it

Environmental Properties of Viscose Rayon

y Silverfish

y Mildew

y Sunlight

End Uses of Viscose Rayon

y Frequently used in blends

◦ Blended with fibers that are more durable

y Most rayon fabrics are woven

y Fiber may stretch when damp or wet

y Nonwoven rayon fabric used in medical and sanitary products

Care of Viscose Rayon

y Dry cleaning recommended

y Nonchlorine bleaches are safe

y Follow care labels!!!

y Store in a clean, dry environment

More Rayon p.67

y Cuperammonium Rayon

◦ Bemberg rayon (bember industries until 1975)

◦ Known as cupro

◦ Silkier in feel and appearance

◦ Lightweight summer clothing

More Rayon

y High-Wet Modulus Rayon

◦ Stronger, more resilient, more dimensionally stable

◦ Modulus refers to resistance to stress + strain

◦ European generic name is Model

y High-tenacity Rayon

◦ stronger than viscose

y Newest regenerated cellulosic fiber

◦ Tencel® by Courtaulds Fibers, Inc.

◦ Lenzing Lyocell® by Lenzing Fibers

Corporation

y Solvent used is nontoxic

◦ Self-contained solvent-spun process

x Creates little water and air pollution

◦ Environmentally friendly fiber

y Process more expensive

Tencel® lyocell fiber

49

Physical Properties of Lyocell

y Fiber is round

y Smooth

y No striations

y Fibrils or tiny fibers on surface

◦ Creates a fine, soft finish with reduced luster

Photomicrograph of lyocell fibers

ITS Intertek Testing ServicesLabtest

51

Mechanical Properties of Lyocell

y Stronger than other cellulosic fibers

y More abrasion resistance

y Less shrinkage

y Better resilience

Chemical Properties of Lyocell

Environmental Properties of Lyocell

y Similar to rayon

◦ Silverfish

◦ Mildew

◦ Sunlight

End Uses of Lyocell

y Apparel & Home Furnishings

y Knits and Wovens

y Due to high cost – limited nonwoven applications

y Frequently used in blends

◦ Especially cotton

Care of Lyocell

y Wash or Dry clean

y Follow care labels closely

y Friction can cause additional fibrillation of fibers

Derivative Cellulosic Fibers

y Acetate and Triacetate

◦ Chemically changed during production

◦ Derivative of cellulose called esters

x FIBERS ARE NOT CELLULOSE

Cellulose Acetate Commonly Called

Physical Properties of Acetate

Photomicrograph of acetate fibers

ITS Intertek Testing ServicesLabtest

60

Mechanical Properties of Acetate

y Very weak fiber

y Lighter in weight than cotton or rayon

y Poor abrasion resistance

y Poor elasticity

y Poor resilience

y Not dimensionally stable

y Does not pill

y Drapes well

Chemical Properties of Acetate

y Moderate absorbency

y Builds static electricity

y Melts at temps over 275

y Thermoplastic

y Resistant to acids and bases

y Can be bleached with nonchlorine bleach

y Not as comfortable to wear as:

◦ Cotton, linen or rayon

Environmental Properties of Acetate

y Susceptible to atmospheric gases

◦ Color may change

y Silverfish if heavily starched

y Mildew

y Sunlight degrades

◦ But less than silk/other cellulosic fibers

◦ Delustered acetate less resistant to sunlight

End Uses of Acetate

y Apparel and Home Furnishings

y Don’t use when durability is needed

y Lining fabric

y Frequently used in:

◦ Taffeta, satin and brocade for formal wear

y Cigarette filters

y Personal hygiene products

y Fiberfill

y Filters

Care of Acetate

y Dry cleaning recommended

y Stay away from acetone

y Nonchlorine bleaches may be used

y U.S production ceased in 1986

y Produced today in;

y Chemical 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)

x creases and pleats are more permanent

y Environmental Properties

◦ More resistant to mildew than acetate

◦ Resistant to silverfish, moths and carpet beetles

◦ Moderate resistant to sunlight

y End Uses

◦ Used when durability is not important

◦ Used when pleat and crease retention is important

◦ Bedspreads

◦ Comforters

◦ draperies

◦ Use non-chlorine bleach

◦ Needs lining for sunlight if used as draperies

◦ Acetone will damage it.

y http://www.youtube.com/watch?v=7mAYMg5ycMs