Yarns

A yarn is a continuous length of fine fibres or filaments with or without twist.
The thickness and tightness of yarn can affect a fabric's weight, flexibility, handle, texture, appearance and end use.

Carding: fibres are detangled and made to lie in the same direction
Spinning: fibres are drawn out and twisted together.
Tex and denier: the systems used to measure the size of yarns and fibres in thickness and weight (often seen in tights).

Twist:

Twist is put into yarns during spinning to make them stronger so they are suitable for weaving or knitting.
There are two different types of twist- S (anti-clockwise) and Z (clockwise). Different affects can be given to fabric using S or Z twist.

Fabrics made from spun yarn usually have a Z twist in warp and an S twist in weft.

The twist level is the number of turns per metre and is the deciding factor for the end use.

Low twist yarns are softer, weaker and more bulky, meaning they are suitable for weft yarns or for knitting.

High twist yarns are strong and hard, making them suitable for weaving, where they need to withstand the tension of the loom.

The importance of twist: It holds the fibres together, adds strength, the more twist, the tighter and stronger the yarn becomes, too much twist, the yarn will untwist and snarl, can be spun clockwise (Z) or anti clockwise (S).

Yarn types:

Staple yarn- made from short staple fibres, these have to be carded so that they all lie in the same direction before being twisted together to form a yarn. May contain fibres of the same type or may be a blend of different fibres. They are hairy (staple fibres), lacks lustre (dull), has a full handle.

Continuous filament yarn- made by lightly twisting filament fibres together. Smooth in appearance, don't trap air so poor insulators, very lustrous (shiny)

Single yarn- or one-ply yarns are single strands composed of fibres held together by at least a small amount of twist. Plying yarn involves twisting together two or more singles, to make a thicker, stronger yarn.

Piled yarn- 2 or more single yarns are twisted together for a thicker, stronger yarn (2 ply or 3 ply yarn)

Cabled yarn- 2 or more piled yarns twisted together like a rope or cable.

Core- spun yarn- staple fibres are twisted around a core of continuous filament- often used in stretchy fabrics with elastane as the core

Fancy yarn- spun to give irregularities such as colour effects or give interest to the fabric. e.g. slub (lumpy yarn), loop, chenille (hairy yarn), boucle (curly yarn)

Chenille- made from leno weave (fabric made with twisted warp yarns and one weft yarn)- meshes and nets

Boucle- made from 3 strands - a loop yarn and loosely woven to allow loops to occur. A binder yarn wraps around the other two and holds them together and a core yarn runs through the middle

Bulked yarn- treated so that they have increased fluffiness and bulk

Textured yarn- synthetic thermoplastic yarns that have been heat processed to have crimps, coils or loops along the length

Marengo- mixing fibres of different colours during spinning

Mottle - spinning from two colours

Fibres and Fabrics: properties and formation

Fibres are the basic building blocks of fabrics. The fibres are twisted or spun together to form a yarn before a fabric can be made.
Fibres - Yarns - Fabrics

Natural fibres- come from plants and animals (protein and cellulose fibres)
Synthetic fibres- all man made from coal and oil
Regenerated fibres- partly made from chemicals, partly from natural things. Made from natural cellulose e.g. wood pulp - man made

Natural fibres-
- cotton (cellulose, seed)
- wool (protein)
- silk (protein)
- hair (protein)
- linen (cellulose, bast)
- ramie (cellulose, bast)

Regenerated fibres-
- viscose (Rayon)
- Modal
- Acetate
- Lyocell (Tencel)

Synthetic fibres-
- polyamide/ nylon (Tactel)
- polyester (trevira, polar fleece/ terylane)
- acrylic (courtelle/ amicor)
- elastane (lycra)

Staple fibre- a short fibre
Filament fibre- a long fibre

Bast fibre- from the stem of a plant e.g. hemp
Leaf fibre- from leaf of a plant e.g. sisal, pineapple, banana
Seed fibre- from seed of a plant e.g. coir

Cotton:
- cellulosic
- grows inside seed pods which burst open to expose the cotton fibres
- a staple fibre

Advantages	Disadvantages
strong, especially when wet can be washed regularly at high temperatures good moisture absorption (good for active wear) breathable can be bleached hard wearing- good resistance to abrasion inexpensive soft handle easy care good drape	good absorption means staining can shrink very flammable creases badly will go mouldy if left damp dries slowly

Linen:

- cellulosic

- fibre is known as flax and called Linen once made into a fabric

- staple fibres

Advantages	Disadvantages
Cool fibre Strongest natural fibre both wet and dry- washes well Hardwearing Lustrous and lightweight Soft firm handle Absorbent by dries quickly Dirt repellent easy care	Creases badly Shrinks up to 15% Very flammable

Ramie:

-cellulosic

-comes from stem of nettle plant

- used for rope, twine, and commercial products

- staple fibre

- silky in appearance

Advantages	Disadvantages
Strong- both wet and dry Highly absorbent Gets smoother when washed comfortable can be washed	creases easily stiff brittle fibres expensive stiff- doesn't drape well not durable little elasticity

Wool:

- protein fibre

- from fleece of sheep

- staple fibre - creates a warm fuzzy fabric

- has a crimp - a wavy structure- can be pulled and will snap back into place - stretchy 

- used for knitwear, jumpers, scarves

Advantages	Disadvantages
Soft full handle- fine wool Warm- many air pockets trapped between fibres Hydrophobic- water resistant- direction of scales allow water to run off Resistant to burning- high moisture Crease resistant Hydrophilic- absorbs without feeling wet good drape good elasticity	Will shrink- scales interlock and felt creating a matted fabric coarse wool- scratchy

The woolmark- indicates a product is made out of 100% wool

Silk:

- protein fibre

- comes from cacoon of a silk moth/ worm

- continuous filament fibre

- used for luxury products, haute couture, lingerie, wedding dresses, evening wear

Advantages	Disadvantages
Very smooth and lustrous Good draping qualities Absorbent- takes dye well Cool in the summer, warm in the winter very comfortable soft handle good strength	expensive creases easily easily damaged by perspiration/sunlight needs to be dry cleaned or carefully handwashed weak when wet

Hair:

- protein fibre

- regarded as rare and expensive

- all from animals

Cashmere- from goat

Mohare- angora goat

Vicuna- from camels

- adds to luxury appearance/ handle of the product

- usually blended with other fibres

Advantages	Disadvantages
Warm Lightweight Very fine smooth fibres Soft texture and handle	Easily damaged by perspiration or sunlight Needs dry cleaning or careful hand washing

Mohair- angora goat:

Advantages	Disadvantages
Warmer than wool Lustrous Light Luxury handle Good drape Durable Crease resistant	Poor absorbency Extreme care

Asbestos:

- mineral fibre

- now restricted due to health hazard

- used to be used where heat protection was required e.g. theatre curtains

- non flammable

- resistant to chemicals

Viscose:

- regenerated cellulosic

-made from wood pulp

How it's made:

- Cellulose sheets are placed in a bath of caustic soda

-both are shredded

- they are thoroughly mixed up

- more caustic soda is added to make a viscose solution

- solution is stored until needed

Advantages	Disadvantages
Highly absorbent Soft Comfortable Good drape	Not strong Creases easily Not warm

Modal:

- regenerated cellulosic

-made from wood pulp

- often blended

Advantages	Disadvantages
Highly absorbent Soft Comfortable Good drape Soft handle Easy care Low shrinkage	Not strong Creases easily Poor elasticity

Lyocell:

- regenerated cellulosic

- made from wood pulp

- branded as tencel

- like cotton but very eco-friendly

- high strength

- absorbent

- breathable

- low shrinkage

Cupro:

- regenerated cellulosic

- made from wood pulp

- breathes like cotton

- drapes beautifully

- feels like silk on your skin

- an elegant fabric

Acetate:

- regenerated cellulosic

- made from wood pulp

Advantages	Disadvantages
Fast drying Soft handle Smooth Drapes well	Low absorbency Low warmth Creases easily Not strong

Rubber:

- regenerated cellulosis

- made from wood pulp

- stretchy

- non-slip

- can be printed onto parts of garment

Polyamide/ Nylon:

- synthetic fibre

Advantages	Disadvantages
Very strong Very durable Easy care Dries quickly Crease resistant Hydrophobic- water resistant Thermoplastic- can be molded when heated	Non- absorbent Prone to static Melts with heat Low warmth static

Acrylic:

-synthetic fibre

Advantages	Disadvantages
Soft Wool like Warm Fast drying Strong Crease resistant Good drape Strong Thermoplastic	May shrink

Polyester:

-synthetic fibres

Advantages	Disadvantages
Fast drying Strong Crease resistant Hydrophobic- water resistant Soft handle Thermoplastic	Low absorbency Low warmth static

Elastane/ Lycra:

- Synthetic

- always blended

Advantages	Disadvantages
Adds stretch/ comfort Crease resistant Absorbent- dyes well Soft thermoplastic	Low warmth

PVC:

-synthetic

- can be used as a protective coating on fabrics

Advantages	Disadvantages
Waterproof Strong durable good insulator breathable fast drying	Stiff/ uncomfortable low absorbency

Microfibres- very fine synthetic fibres made from polyamide (nylon) or polyester. When made into a fabric it is very soft to touch, has excellent draping qualities and good strength- used in smart fabrics and high performance active wear

Shape and formation of fibres:

The way fibres are formed (natural or man-made) has an affect on the properties that they have. For example wool fibres naturally have scales that trap air so they are warm. 

Synthetic fibres are produced by extruding the liquid polymer solution through a spinneret into either warm air (dry spinning), cold air (melt spinning) or fluid (wet spinning). This results in long smooth continuous filament fibres.

Dry spinning: The polymer solution is extruded in a stream of warm air. This evaporates the solvent and solidifies the filament. - acetate and acrylics

Melt spinning: synthetic polymer chips are melted, extruded through a spinneret and hardened in cool air.- nylon and polyester

Wet spinning; polymer solution is extruded into a chemical fluid which solidifies the filaments- viscose and acrylics