1. Knitted fabrics are made from interlocking loops of yarn.
There are two main types of knitting:
WEFT KNITS
WARP KNITS
In weft knitting the loops of yarn are linked across the width of the fabric.
In warp knitting the loops are linked in a vertical direction.
To recap on what we know about fabrics – they can be woven, non-woven or knitted. Today, we are going to learn a little bit more about knitted fabrics.
Knitted fabrics are made from interlocking loops of yarn. Depending on the type of knit construction, this will either be a single yarn, or several yarns. If the loops are broken, the fabric will easily come apart.
There are 2 types of knitted fabric: WARP & WEFT.
Warp knitting machine

2. Weft Knitting
Weft knitting is made using a single yarn. It can be made by hand knitting or by machines.
Characteristics of weft knits:
The fabric has high elasticity and stretch.
The loops of yarn trap air which retains body heat to keep us warm.
The right and wrong sides of the fabric look different.
the fabrics can lose shape easily.
Creases fall out easily.
The fabric can unravel and ladder easily.
Weft knitted fabrics curl up at the edges when they are cut.
Weft knitting is the type we generally think of as a knitted fabric. It can be be very heavy gauge (thick & chunky) or very fine gauge (used for T-shirts & underwear).
Weft knitting uses a single yarn & the loops are linked across the width of the fabric. It can be done by hand or by machine. This type of knitting can unravel, & will ladder if a stitch is dropped, or the yarn is broken (think of what happens to your tights if you snag or catch them on something).
I’m going to show you some clips of how the knitting is formed, & then we’ll have a go at producing a bit of our own.

3. Weft Knitting Weft knitting machines being used in industry:
What this looks like in slow motion:
How to knit by hand:
In industry, warp knitting is made on huge computerised machines. These can be flat bed, V-Bed or circular machines. We’ll have a look at a clip of a flat bed machine.
The 2nd clip is of a home-made knitting machine. Its much slower but it shows quite clearly the single yarn going across the bed of needles & the loops that form each stitch. It’s these stitches that give knitting its V-shapes.
(If clip doesn’t work, put in ‘knitting machine – handmade’ into search engine on You Tube)
The last clip is of hand knitting. Watch closely, as we’re going to have a go at knitting this stitch ourselves. It’s the most basic knitting stitch & is called the garter stitch.

4. Warp Knitted Fabrics
In warp knitting the yarn loops vertically up the fabric and the process uses many yarns rather than one. The fabric does not unravel or ladder. It is an industrial process only.
Warp knitting uses lots of different yarns which are looped together vertically as well as horizontally. The fabric doesn’t unravel when it is cut, so it won’t ladder.
It is very fast to produce. The fabric is elastic but will still keep its shape. However, the machinery is very complicated, so the fabric can be expensive to produce.
Warp knitting is used to make lace & nets (such as lace curtains) & a fabric called lock-knit which is used for bed sheets, furnishing fabrics, velour & swimwear.
Characteristics of warp knits:
The production system is fast so the fabrics are quick to make.
The fabric is elastic but it can keep its shape.
It can be cut and sewn easily as it lies flat when cut.
It is mainly used with synthetic filament yarns.

5. Warp Knitting A warp knitting machine
Making a narrow lace trim
Warp knitting machines can be used to make lace which is currently very on-trend & fashionable.
This 1st clip shows a modern warp knitting machine & you can see that there are many yarns being knitted & looped together
(if clip doesn’t work, click on the thumbnail on the right that is called 1.m2ts)
The 2nd clip shows an older piece of machinery using many small bobbins of yarn to make narrow lace trims.
(if clip doesn’t work, click on thumbnail entitled lace making machine, then on another thumbnail for same thing but a darker image, as this is a better clip).

6. Uses of Knitted Fabrics
Weft Knits
T-shirts
Jumpers
Cardigans
Sweatshirt fabrics
Warp Knits
Net curtains
Swimwear
Terry towelling fabrics
Patterned tights
Lace fabrics
So finally, a quick re-cap on some of the products that are made from knitted fabrics.
If there is time, & the plexi-scope is working, show the knitted construction under the microscope.

7. Exam questions

8. Manufactured Synthetic Fibres
Learning Objectives:
Understand the sources, properties and uses of manufactured synthetic fibres.
Identify the advantages and disadvantages of manufactured synthetic fibres.

9. Manufactured Synthetic Fibres – Polyamide (Nylon)
Properties:
Very strong
Hard-wearing
Does not decompose (rot)
Melts as it burns
Not very absorbent so it dries quickly
Crease resistant
Resists alkalis but can be damaged by acids.
Versatile - can be made into many types of products.
Advantages:
Strong when wet
Inexpensive
Resists bacteria
Durable and long lasting
Disadvantages:
Can be damaged by sunlight which discolours it and makes it weak.
Low absorbency
Not always comfortable to wear.
Uses:
Clothing
Ropes
Carpets & rugs
Seat belts
Fabric Names:
Nylon
Tactel
Tactel Micro

10. Manufactured Synthetic Fibres- Polyester
Properties:
Very strong
Can be made flame resistant
Thermoplastic – can be heat set into pleats and shapes.
Does not decompose
Resists most alkalis but can be damaged by acids.
Versatile as it can be made into many types of products.
Fabric Names:
Terylene
Polar Fleece
Trevira
Finesse
Miratec
Dacron
Uses:
Sportswear
Ties
Sewing threads
Medical textiles
Net curtains
Carpets
Disadvantages:
Poor absorbency so it is difficult to dye.
Advantages:
Strong when wet
Dries quickly
Crease resistant
Cheap
Resists bacteria

11. Manufactured Synthetic Fibres - Acrylic
Properties:
Strong when it is dry but weaker when wet.
Shrinks away from heat.
Thermoplastic
Burns slowly then melts.
Soft
Warm
Easy to wash and dry.
Advantages:
Warm
Soft
Insulating
Inexpensive
Dries quickly
Disadvantages:
Poor absorbency
Fabric Names:
Courtelle
Amicor
Uses:
Knitwear Upholstery fabrics
Fake fur Sportswear
Toys

12. Manufactured Synthetic Fibres - Elastane
Properties:
Very elastic
Lightweight
Very strong
Resists chemicals
Not damaged by perspiration
Aids crease resistance
Advantages:
Very stretchy
Keeps its shape
Resistant to damage by sun and seawater
Lightweight
Strong
Makes garments comfortable to wear
Disadvantages:
Very poor absorbency
Always needs to be blended with other fibres. It is too stretchy and elastic to be used on its own.
Uses:
Swimwear
Sportswear
Jeans
Fabric names:
Lycra

13. Regenerated Cellulose Fibres
Regenerated cellulose fibres are made from wood pulp and chemicals. They are similar to cotton.
Names of regenerated fibres:
Viscose Rayon Acetate
Triacetate Modal Tencel
Lyocell
Uses:
Lyocell is used as a non woven fabric for medical wipes and swabs.
Fashion clothing
Lingerie
Ribbons
Protective clothing
These are environmentally friendly fibres because they reuse waste chemicals in the production process.
Properties of Regenerated Cellulose Fibres:
Highly absorbent
Washable
Soft
Smooth
Comfortable to wear
Drape well
High strength when wet

14. Exam questions

15. Natural Fibres Learning Objectives:
Understand the sources, properties and uses of natural fibres.
Identify the advantages and disadvantages of natural fibres.

16. Natural Plant Fibres - Cotton
Properties:
Strong
Absorbent
Cool to wear
Hard- wearing
Creases easily
Smooth
Versatile
Easy to care for
Breathable
Fabric Names:
Calico Drill
Corduroy Poplin
Denim Velvet
Advantages:
Strong when wet
Durable & long lasting
Not expensive
Environmentally sustainable
Comfortable to wear
Disadvantages:
Creases easily
Burns easily
Shrinks when washed
Uses:
Soft furnishings such as cushions and curtains
Clothing such as jeans and T-shirts
Knitting yarns

17. Natural Plant Fibres - Linen
Properties:
Very hard-wearing
Cool next to the skin
Strong
Absorbent
Creases easily
Dull lustre
Breathable
Fabric Names:
Duck Huckabuck
Mattress Ticking Holland
Uses:
Light weight summer clothing
Tea towels
Sheets
Table cloths
Disadvantages:
Creases easily
Expensive
Advantages:
Strong when wet
Very hard-wearing
Highly absorbent so dyes easily
Comfortable to wear

18. Natural Animal Fibres - Wool
Properties:
Warm
Absorbent
Low flammability
Good elasticity so creases drop out easily
Comfortable to wear
Fabric Names:
Lambswool
Merino
Superwash
Felt
Harris Tweed
Gaberdine
Uses:
Warm outer wear such as coats
Jumpers and cardigans
Blankets
Carpets
Advantages:
Warm and insulating
Does not crease easily
Comfortable
Can be produced in a wide range of weights of fabric.
Disadvantages:
Can shrink & felt when washed
Takes a long time to dry as it is very absorbent
Some types can be itchy next to the skin

19. Natural Animal Fibres - Silk
Properties:
Absorbent
Soft and comfortable
Cool but also warm and insulating when worn in layers
Natural sheen and lustre
Strong when dry
Fabric Names:
Chiffon Duchess
Crepe Organza
Dupion Taffeta
Advantages:
Soft, smooth and lustrous
Drapes well
Comfortable to wear next to the skin
Disadvantages:
Expensive
Can be weak when wet so it needs careful washing or dry cleaning.
May crease easily
Uses:
Luxury clothing such as lingerie, evening and bridal wear.
Knitwear
Soft furnishings

20. Exam questions

21. Regenerated Fibres
Definition: Regenerated fibres are made from wood pulp (cellulose). They are partly natural and partly synthetic as a chemical is needed to extract the fibres.
They way the fibres are produced differs from fibre to fibre.
It can be done through wet spinning and dry spinning or even melt spinning. All cellulose fibres are either wet or dry spun or a combination of both.

22. Viscose Cellulose sheets are placed in a bath of caustic soda.
Both are shredded
They are thoroughly mixed up
More caustic soda is added which makes the viscose solution.
Solution is stored until needed.

23. Wet spinning
The fibre solution is pressed through the spinneret
It enters the acid bath which causes the fibres to set.
Filaments are passing through a set of heated rollers that will further set the fibre.
They are wound onto godet wheels ready for spinning.
Pollution
Viscose currently is becoming less common because of the polluting effects of carbon disulfide and other by-products of the process, forcing some factories to close.

24. Properties
Viscose drapes and swings beautifully and the material is softer than cotton and more springy than silk.
It is comfortable to wear and is great for dyeing. Viscose is a lovely fabric for floaty summer skirts, figure-hugging dresses, and underwear you want someone to notice.
Uses:
Jersey, suits, dress fabric and lining.

25. Viscose is a solution made from woodchips
What do you know
Viscose?
Viscose is a solution made from woodchips
False. It is a solution made from cellulose sheets dipped into caustic soda.
Which spinning process is used to produce Viscose?
Wet spinning
Which liquid is the spinneret placed into?
Acid
Viscose pollutes the environment due to the by products of the viscose process. Which chemical causes the problem?
Carbon disulfide
It drapes well, is soft & comfortable to wear
Give an example of viscose fabric qualities
Give an example of a property of the viscose fibre
It’s a filament, its soft has more elasticity than silk and is lustrous.

26. Lyocell & Tencel
Lyocell is produced from wood pulp cellulose. It is marketed under the brand name Tencel. It is the modern Rayon!
It that it is soft, absorbent, very strong when wet or dry, and resistant to wrinkles; it can be machine- or hand-washed or dry-cleaned, it drapes well, and it can be dyed many colours, as well as simulating a variety of textures like suede, leather, or silk.
It is biodegradable.

27. Making process:
Dissolve the wood pulp in a chemical which creates a solution called “dope”.
The dope is then pushed through a spinneret to form the individual fibres.
It is washed and the chemicals are retrieved from the water, purified, and recycled.
Since there is little by product, this process is labelled as relatively eco-friendly. However, it uses a substantial amount of energy and the solvent is a by-product of petrol production.
coagulation bath
Dry/wet spinning

28. Uses:
Staple fibres are used in apparel items such as denim, chino, underwear and other casual wear clothing, even in bath towels. Filament fibres are used in items that have a silkier appearance such as women’s clothing and men’s dress shirts and medical dressings. Tencel is also used for making baby diaper wipes.
Fibres blends:
Look for Tencel® lyocell blended with Tactel® nylon in which the Tactel® is on the surface for durability and wind and water resistance, while the Tencel® has greater exposure on the backing surface for warmth, absorbency, and comfort.

29. Acetate Properties of cellulose acetate: Good toughness
Deep gloss
High transparency
A feel that can be
described as ‘natural
comfortable,
Breathable and absorbent
Natural and Renewable
It is manufactured using wood pulp as a raw material.
Wood pulp is a renewable resource grown in closely managed wood pulp forests.

30. Viscose is a solution made from woodchips
What do you know
Tencel & Lyocell?
Viscose is a solution made from woodchips
False. It is a solution made from cellulose sheets dipped into caustic soda.
Which spinning process is used to produce Viscose?
Wet spinning
Which liquid is the spinneret placed into?
Acid
Viscose pollutes the environment due to the by products of the viscose process. Which chemical causes the problem?
Carbon disulfide
It drapes well, is soft & comfortable to wear
Give an example of viscose fabric qualities
Give an example of a property of the viscose fibre
It’s a filament, its soft has more elasticity than silk and is lustrous.

31. Production of Acetate
The production of cellulose acetate fibres is clean and meets all environmental regulations. Also, acetone is a biodegradable solvent.
Cellulose acetate has been shown to be biodegradable and can be composted or incinerated.
The acetone used in the manufacturing process is recovered (up to 95-98%). guidelines.
Dry spinning

32. Uses:
Ties, lingerie, and bathing suits, lining, dress fabric.

33. What are regenerated fibres made out off? Cellulose
What do you know about
Regenerated Fabrics?
What are regenerated fibres made out off?
Cellulose
What do you need to make the wood pulp into a fibre?
A chemical
Which two spinning methods are there to make a generated fibre?
Dry/wet spinning
Which products are made from Acetate?
Lining, dress fabric & ties
Which products are made from Viscose?
Lining, dress fabric & jersey
Which is the least environmentally friendly regenerated fibre?
Viscose
Which regenerated fibres have a poor crease recovery?
Viscose & Acetate
Which R.F. have good crease recovery?
Tencel & Lyocell