Finishes Flashcards
1
Q
Why do we add finishes?
A
- to protect the fabric or design features
-to change the handle (feel), resilience, durability or look of the fabric - or add value to the product
2
Q
What are the 3 categories that finishes lie in?
A
Physical, Biological, Chemical
3
Q
What are physical/mechanical finishes?
A
- Dry processes that are applied physically without the use of water or chemicals
- used to modify the fabric surface.
4
Q
Examples of physical/mechanical finishes
A
- Brushing
- Calendering
- Embossing
- Heat-setting
- stone and sand washing
5
Q
What is Calendaring?
A
- uses heat and pressure to smooth the fabric surface
- rollers can be set at different speeds & temperatures giving fabrics different finishes (e.g. Moire effects)
6
Q
What is Embossing?
A
- synthetic fabrics are passed through pattern engraved heated rollers
- leaves the embossed pattern on the fabric
- disappear when washed & ironed unless synthetic fabric is used (as can be heat-set)
7
Q
What is brushing?
A
- produces a nap and traps air
Example: cotton fabrics are made softer and warmer to wear but more flammable - fabrics are passes between a series of wire rollers which brush the fabric
- leaving it soft & fluffy but weaker
- commonly used on cotton fabrics & polyester fleece fabrics
8
Q
Examples of biological finishes
A
- Biostoning
- Biopolishing
9
Q
What is Biostoning & Biopolishing?
A
Biostoning - A process of subjecting the fibre to cellulase enzyme as an alternative to rubbing with pumice.
Biopolishing - A process of adding a sheen to the fabric using a biological enzyme.
10
Q
What are chemical finishes?
A
- wet processes that use chemicals and heat, occasionally water
- change the fibre structure or fabric properties in order to improve their characteristics
11
Q
Examples of chemical finishes
A
- mercerisation
- flame retardancy
- water resistance
- crease resistant
- shrink resistant
12
Q
What is mercerisation?
A
- used on cotton fabrics
- treat fibres with caustic soda (strong alkali)
- causes cotton fibres to swell & shrink
- changes ribbon-like flat fibre to smoother one with circular cross-section
- adds strength, gives lustre, makes cotton better at absorbing dyes
13
Q
What is flame retardancy?
A
- prevent the fabric from setting on fire, or prevent it from burning quickly
- nightwear fabrics (cotton and viscose) can be treated with proban or pyrovatex which contain a polymer that is trapped within the fibres, and is not removed by washing
- this gives the fabric a flame retardant finish and makes it stiff and reduces its tearing strength
14
Q
What is water resistance?
A
- prevent staining from water-borne stains and protect fabrics from being penetrated by rain and water
- silicone treatments are used for this, e.g. Scotchgard
- Teflon is a surface finish that provides an invisible barrier to prevent water and oil-based stains from penetrating the fibres
- used on clothing (e.g. school uniforms, tents, raincoats)
- Teflon doesn’t affect the feel, appearance, or breathability of the fabric, and makes it easier to iron
