2B Yarns

Question 1

What is a staple yarn?

Answer 1

Yarn made from short staple fibres that are carded/combed (so they all lie in the same direction), then twisted together to form a yarn

Question 2

Features of staple yarns

Answer 2

Hairy:
- good insulators: makes them good at trapping air between fibres (makes fabrics that are warm)
- can trap moisture between fibres
- more texture than smooth yarns
- duller/matte in appearance
- gives fabrics texture and a soft/fuller handle

• more expensive to manufacture: more stages and energy required
• can contain two or more different types of fibre (blended for aesthetics/performance/aftercare)

Question 3

How are filament fibres used to make staple yarns?

Answer 3

• the filament fibres can be chopped up into short staple fibres, which need to be twisted together to make a yarn
• if filament fibres want to be blended with staple fibres: the long filaments need to be cut into staple before being spun

Question 4

What is a filament yarn?

Answer 4

Yarn made by lightly twisting one or more filament fibres together

Question 5

Different types of filament yarn

Answer 5

• Multifilament: yarn made by lightly twisting continuous filament fibres together
• Mono-filament: yarn made from a single, continuous filament spun from a spinneret with one hole

Question 6

Features of filament yarns

Answer 6

• smooth: do not trap air between fibres (fabrics are not good insulators)
• more lustrous, smoother and regular than staple yarns (stronger)

Question 7

Features of fabrics made from filament yarns

Answer 7

• more compact handle
• higher degree of lustre
• not good at insulating

Question 8

Silk filaments

Answer 8

• very fine
• need to be lightly twisted with other silk fibres to be made into usable yarn

Question 9

What is single(one-ply) yarn?

Answer 9

One continuous single thread of twisted staple/filament fibres/monofilament/filaments grouped together with little or without twist to make a single yarn

Question 10

Man-made fibres

Answer 10

• extruded from a spinneret as continuous filaments
• filaments can be grouped together with or without twist to from multifilament yarn

Question 11

What is plied(folded) yarn?

Answer 11

Yarn made by twisting two or more single yarns together to make a thicker yarn

Question 12

What does the ply of the yarn represent?

Answer 12

Refers to the number of strands that the yarn is made up of (e.g. 2-ply/4-ply)

The higher the ply number, the more durable the yarn is compared to those with lower numbers as the plies hold the fibres together more tightly

Question 13

Features of plied yarns

Answer 13

• can achieve special effects by using yarns made from different fibres/colours (plied/corded/cabled)
• yarns with more than one ply can be twisted together to make corded yarns (e.g. sewing and embroidery threads/industrial yarns - strong)
• the thickness and weight of the yarn depends on the individual strands used to make the yarn, not only the number of plies

Question 14

How are plied yarns made from staple yarns?

Answer 14

The single yarns are twisted together in the opposite direction to the direction that they were spun - achieves uniform thickness and strength

Question 15

What is a corespun yarn?

Answer 15

A multicomponent yarn with a central core yarn that is covered by other outer fibres (sheath) made from staple/filament yarn

Question 16

Features of corespun yarns

Answer 16

• important for the manufacture off stretch yarns/sewing threads/metallic yarns
• the filament core: can provide strength
• weaker outer fibres: used for aesthetic purposes (e.g. metallic yarn)

Question 17

Methods of core-spinning fibres

Answer 17

1. Twisting a sheath of fibres around a core (different fibre): yarn made using this method usually has a filament yarn/elastometric fibre core and a synthetic/natural fibre sheath
2. Stretching the elastane core yarn and covering it with one/two strands of non-elastic filament yarn(can be natural/synthetic/blend), wrapped in opposite directions to balance the yarn

Question 18

What is textured yarn?

Answer 18

A continuous filament yarn that has crimps, crinkles and snarls set into the filaments

Question 19

Features of textured yarn

Answer 19

• yarns made from synthetic filament fibres: smooth/lack texture/poor insulators
• characteristics of continuous filament fibres can be changed by introducing crimps/crinkles/snarls into filaments: able to trap air (better insulation)

Question 20

Fabrics made from texture yarn

Answer 20

Texture processes adds bulk and interest to yarns which makes fabrics:
- softer: more volume, less lustre
- more extensible
- better insulators
- able to retain/wick moisture away from the body: fine tubes created in and between to help carry water
- crinkles and snarls allow the yarn to stretch out more than untextured yarn: higher elasticity

Question 21

Methods of texturing yarn

Answer 21

1. False-twist texturing: smooth thermoplastic filament yarn is tightly twisted, heat-set and untwisted - the yarn will have crinkles and snarls (method depends on the thermoplastic nature of man-made fibres)
2. Air-jet texturing: a jet of compressed air creates loops and tangles

Question 22

What can textured yarn used to manufacture?

Answer 22

• sportswear
• swimwear
• underwear
• tights

Question 23

What is fancy yarn?

Answer 23

Yarn that has irregularities and other effects added to the length of the yarn to add interest

Question 24

Features of fancy yarn

Answer 24

• usually have a core, binder and effect yarn: all can be made out of any fibre and can be staple/filament
• provide multicolour effects by mixing fibres dyed different colours Or by plying two or more different coloured yarns
• changes the appearance and handle of fabrics
• made using special spinning processes

Question 25

Types of fancy yarn

Answer 25

• boucle yarn: looped yarn - can add colour/textured bumpy feel to woven/knitted fabrics
• slub yarn: made by changing the spinning seed at irregular intervals to produce yarn with thicker/thinner sections - gives uneven texture (similar to fabrics made from linen/wild silk)
• chenille yarn: made by weaving then cutting open, net-type fabric into strips - cut fibres jut out around the central core (gives fabrics a fuzzy/bulky/soft appearance)
• metalled yarn: gives an iridescent effect - used to make fabrics such as lame and brocades