Yarns Flashcards
What is a “drawing” process
The process in which gives synthetic fibres their strength because the chain of molecules become oriented and lie parallel when it’s turning from liquid to solid
It is difficult for water molecules to penetrate between tightly packed fibre molecules in crystalline. True or false.
True
What is extensibility
The measure of how much a fibre will stretch or extend before it breaks
What is crystalline regions
High orientation areas
What are amorphous regions
Low orientation areas
Fibres with lots of crystalline regions tend to be…
Stiff and inflexible
If a fibre has a mix of crystalline and amorphous regions the fibre is able to be….
Stretched or bent
Fibre properties are related to the internal fibre structure. Name three
- Strength
- Ability to absorb moisture
- Extensibility and elastic recovery (crease)
What are three industrial spinning processes called?
Wet, dry and melt spinning.
Why are fibres needed to be made up into yarns?
So they can be woven or knitted into fabric.
How are continuous filament yarns made?
By lightly twisting filament fibres together.
How are staple yarns made?
These short staple yarns have to be carded or combed so that they all lie in the same direction, before being twisted together to form a yarn.
Filament fibres can be chopped up into short staple fibres. True or false.
True.
Staple yarns create hairy yarns. Why is this good?
They trap air between the fibres, so they can insulate well and trap moisture between the fibres too! Smooth yarns have the opposite effect.
If a fabric is to be brushed, the yarn has to be twisted more. True or false.
False. The yarn has to have a low twist.
Denier is worked out by weighing a specific length of the filament fibre or yarn. The thicker the filament fibre or yarn the….
Higher the number of denier. Eg tights.
Folded yarns are made by twisting together at least two single yarns. What does this do?
Improve strength
Eliminate twist liveliness
Make heavier structures
Achieve special effects
What are cabled yarns?
Cabled yarns require more than one twisting stage. Two or more folded yarns may be twisted together to form a cable yarn.
What are core-spun yarns?
Made by covering a core filament yarn with staple fibres in a single spinning process. Can be used for elastic fabrics, with the elastane filament covered by natural fibres.
What types of effects can fancy yarns create?
Coloured
Structural
Lustre
Fancy yarn: Mixture. How is this made?
Mixing fibres of different colours during spinning, creates heather effect.
Fancy yarn: Bouclé. How is this made?
Made by a special folding process, results in a wavy loop projections.
Name four fancy yarns?
Mixture
Chenille
Crêpe
Bouclé
What are the three groups of textured yarns?
Stretch yarns
Stabilised yarns
Bulked yarns
What is stretched yarns
Highly elastic yarns
What are stabilised yarns
Yarns which have been given setting treatment to reduce their elasticity
What are bulked yarns?
Voluminous yarns with crimps and loops
