Unit 3 Lecture 15 Topic 1

Question 1

Yarns:

Answer 1

A yarn is a continuous strand of textile fibres, filaments, or materials in a form suitable for knitting, weaving, or otherwise intertwining to form a textile fabric.

Question 2

What is another name for yarns?

Answer 2

A thread.

Question 3

Staple yarn:

Answer 3

Composed of short staple fibres held together by spinning (twisting). It also may be called a spun yarn.

Question 4

Filament Yarn:

Answer 4

Composed of long single filament or multiple filaments grouped together and slightly twisted. Filament yarns are made from manufactured fibres or from filament silk. It is made by extruding a polymer solution through a spinneret and solidifying it in fibre form. Individual filaments are brought together with or without a slight twist.

Question 5

What is the texture of filament yarn?

Answer 5

Filament yarns can be straight and smooth, or have texture added during its manufacture.

Question 6

Spun yarns:

Answer 6

Spun yarns are continuous strands of staple fibres twisted together. Their fibre ends protrude and the filaments can be cut into staple lengths and turned into spun staple yarns. They are often blended with natural fibres to impart the properties of each fibre to the yarn.

Question 7

What is the durability of yarns like?

Answer 7

Filament yarns are generally stronger than spun yarns as all these continuous fibres are contributing to yarn strength.

Question 8

How does absorbency differ between staple and filament yarns?

Answer 8

Staple yarns are generally more absorbent than filament yarns because of the air spaces within the yarn structure and because there is more fibre surface area.

Question 9

How does water vapour permeability differ between staple and filament yarns?

Answer 9

Staple yarns have higher water vapour permeability as filament fibres allow for closer packing within the yarns. Staple yarns do not lie as closely together as filament yarns.

Question 10

How does insulation differ between staple and filament yarns?

Answer 10

Staple yarns provide higher insulation because of air trapped between fibres. Although worse, textured filaments are warmer than smooth filament yarn.

Question 11

How does the standard temperature of textiles differ between staple and filament yarn make-up?

Answer 11

Fabrics from staple and textured filament yarns feel “warmer” to touch.

Question 12

How do staple yarns appear?

Answer 12

Staple yarns are softer, less lustrous and have more covering power. However, they do lint and pill more than filament yarn

Question 13

How do yarn filaments appear?

Answer 13

Filament yarns snag more readily than staple yarn fabric (especially smooth/flat filament). They also shed oily soil better than staple yarns, but this depends on fibre content.

Question 14

Into what categories can yarn be classified?

Answer 14

Simple yarns, complex yarns, and composite yarns.

Question 15

Simple yarns:

Answer 15

Simple yarns are uniform in size and structure where all parts are alike. They can be staple/spun or filament. There are three types of simple yarns; Single yarns, pllied yarns, and cord yarns (a.k.a cable).

Question 16

Complex yarns:

Answer 16

Complex yarns (fancy or novelty yarns) have deliberate unlike parts and are produced for aesthetic effects. They are single or plied yarns with irregularities along their lengths which may be subtle or obvious, and regular or random.

Question 17

Composite Yarns:

Answer 17

Covered, core-spun, and filament-wrapped yarns that are regular in appearance along their length. Composite yarns have both staple-fibre and filament-fibre components or elements.

Question 18

Yarn Number/Yarn Count

Answer 18

Yarn size or fineness. Yarn Number is the linear density expressed as mass per unit length.

Question 19

Tex:

Answer 19

The gram weight of 1,000m (1 km) of yarn.

Question 20

Dtex:

Answer 20

The gram weight of 10,000 m (10 km).

Question 21

Denier:

Answer 21

The gram weight of 9,000 m (9 km).

Question 22

What is the tex, decitex & denier of a yarn, if 10 m of the yarn weighs 0.2 g?

Answer 22

Dtex = 200
Denier = 180
Tex = 20

Question 23

How does yarn size affect the yarn?

Answer 23

As yarn size increases, the thickness, weight and stiffness of the fabric increases. Fine yarns (lower tex) produce softer and more drapeable fabrics. As yarn size increases, the yarn strength increases.