Textiles Technology (OCR)

Spinning - Yarns:

• This is the method used to convert bundles of fibres into years by twisting ('Z' or 'S' twists).
• Most natural fibres are shorts - staple fibres - these needs to be carded to make the fibres run parallel to each other before spinning.
• Man-made fibres (and silk) are very long fibres - continuous fibres - these need very little spinning to make a strong yarn.
• When man-made fibres are converted from a liquid to a solid (as they pass through the spinneret) the hardening method is also called spinning: melt / wet / dry
• Single yarns twisted together to make multiple yarns = plying (eg: three single yarns twisted together = 3 ply yarn)
• Yarns are made in a variety of fibres, thickness and textures = fancy and novelty yarns.

Weaving:

• Manufactured on a loom - interlacing yarns at right angles to eachother. 
• Key terms: warp / weft / selvedge / shuttle / heddle / reed / bias / straight grain (grain line)

• Weave Patterns:
• Plain - smooth surface - printing, basic weave, cheapest to produce (calico, poplin, muslin, gingham)
• Twill - diagonal lines on surface, RS/WS different, firm fabric (denim, chino, drill)
• Satin - smooth, drape, can pluck easily (satin, sateen)
• Jacquard - fabrics made with a mixture of each of the three weave patterns named above
• Pile (Loop) - loops on surface trap air (insulatiton) and moisture (absorbency) (towelling)
• Pile (Cut) - needs care when cutting out to make pile run in the same direction = nap (velvet, corduroy, fake fur)

Knitting:

• Made from interlocking loops = elasticity/ insulation/ drape/ crease resistance
• Weft knitting - hand knitting and some machine knitting. One yarn source - loops interlock horizontally. Can ladder. Knit to shape of garment.
• Warp knitting - machine knitting. Multiple yarn sources - loops interlock vertically. Can be quite firm. Quicker to make than woven fabric. Knitted as fabric sheets then garment shapes cut out. Fabric edges need to be overlocked to prevent fraying.
• Garments can be circular knitted, eg: tights, seam free underwear.

Non-Woven:

• Fibres are converted directly to fabric. A fibre web is held together by: stitching, felting (heat and beat), glueing, tangling.
• Fewer production stages (no yarn production) = cheaper to produce.
• Used mainly for disposable textiles - not very durable. No grain line = no flexibility but also no fraying

(NB: You need to be able to identify the different weave patterns from a diagram.)

Natural Fibres:

• Plant Fibres (cellulose) - cotton and linen (flax)
• Animal Fibres (protein) - wool and silk
• 'Enviromentally Friendly' - sustainable (renewable), biodegradable, organic
• Cotton - cotton plant (boll). Short fibres (staple), good absorbency (dye deep colours), low elasticity - creases easily, cool to wear, can wash at high temperature, strong when wet than dry
• Linen - flax plant. Low elasticity, creases easily, good absorbency, expensive - many production stages
• Wool - sheep, goats, llama, camels, rabbits. Staple fibres - longer fibres make better quality yarn/fabric, scales (felting - interlock and shrink with heat and moisture), crimp = resilience/ 'bounce' and insultation
• Silk - caccoon. Continuous filament - cacoon unravelled during proudction (silk moth dies inside boiled cacoon). If moth eats through cacoon - short fibres which have to be spun into silk yarn.

Regenerated Fibres - viscose, acetate, triacetate, modal and lyocell:

• Made from naturally fibre forming raw materials (cellulose) - wood pulp (sustainably managed pine or beech forests - FSC)
• Cellulose chemically treated to make a sticky (viscose) liquid - forced through spinneret - solidified (wet or dry spinning) = fibre
• Similar performance and appearance as cotton (but cheaper to manufacture)

Manufactured (Synthetic) Fibres - polyester, polyamide (Tencel), acrylic and elastane:

• Made from chemicals - coil and oil
• Non-renewable and not biodegradable = damage to the enviroment (during extraction, transportation, manufacture and disposal)
• Can be adapted to meet a range of needs - most SMART and modern fibres are based on the development of manufactured fibres.
• Performance characteristics - thermoplastic, hydrophobic (don't absorb water or dye!), warm to wear - traps body heat, strong and durable.

Performance Characteristics:

• This means the properties that fibres have, eg: insulation, absorbency, strength, washability, elasticity, flame resistance
• This is important when choosing a fibre/fabric for a particular end-use