Fabric finishes- 1.4 Flashcards

1
Q

what do fabric finishes do?

A

modify a fabric to improve it or give it properties it does not naturally possess

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2
Q

when is the most efficient time to add a fabric finish?

A

before a product is manufactured- however a finish such as pernament creases can be heat set into garments made of synthetic fabrics

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3
Q

what are the advantages of fabric finishes?

A

-most fibres have disadvantages that can be cancelled out by applying fabric finishes

-finishes enable specific products to conform to British standards- e.g making children’s nightwear fire resistant

-improves the function, performance and aesthetics of a product

-can extend a product’s life span

-they improve easy-care performance, which is beneficial for both the consumer and the environment

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4
Q

what are the disadvantages of fabric finishes?

A

-an additional process which can cost money

-some fabrics need several finishes to make them suitable for their intended use

-some finishes have negative effects on fabrics

-some finishes are semi-permanent

-the chemicals used in finishes and their application can have a negative effect on the environment and the health and well-being of factory workers

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5
Q

mechanical finishes…

A

modify a fabric’s surface using dry processes. applied using machinery

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6
Q

what is the brushing/raising finish used for?

A

producing a nap and trapping air

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7
Q

what happens in a brushing/raising fabric finish?

A

the fabric is passed through a raising/brushing machine which has small wire hooks which tease out the end of the fibres, making them stand up. the other ends of the fibres remain twisted within the staple yarn so that the fibres are not completely detached.

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8
Q

what are the reasons for using a brushing fabric finish?

A

-can be used on fibres such as cotton which are naturally cool fibres
-some products need to be warm to wear
-some fabrics need to be hard/rough
-gives fleece fabric it’s structure

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9
Q

what does brushing/raising fabric finish do?

A

-raises the nap
-traps air- making the fabric much more insulating and softer
-adds bulk/texture
-increases warmth
-softens fabric
-weakens fabric- brushing is a permanent finish
-increases flammability

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10
Q

what are some examples of brushed fabrics?

A

-brushed cotton
-cotton flannelette

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11
Q

what is the nap?

A

The natural direction in which the fibres lay

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12
Q

how is a calendaring fabric finish done?

A

fabric is fed through rotating pressurised heated rollers. The heated rollers flatten/iron the fabric which makes it smoother. by rotating at different speeds and by using different types of rollers, different degrees of lustre and effects can be created.

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13
Q

what appearance does calendaring give?

A

-produces a smooth, lustrous appearance on the surface of the fabric
-compacts the surface of the fibre by closing the gaps created by the weft and warp yarns, making it less penetrable by air and water
-all of these appearances are not permanent!

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14
Q

what are the reasons for calendaring being done?

A

-some fibres such as cotton have no natural lustre- this is because cotton fibres are flat and twisted and do not reflect light
-another reason for calendaring is that it can make a fabric slightly better at resisting soiling

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15
Q

what is embossing?

A

a type of calendaring process

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16
Q

how is embossing done?

A

a pattern is stamped into a fabric as it is passed through heated, pressurised rollers with patterns engraved on them. The finish is permanent when heat-set into fabrics made of thermoplastic properties.

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17
Q

what appearance does embossing give?

A

-creates raised or sunken patterns and textures on fabrics
-simulates a grain texture on synthetic leather products

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18
Q

what type of fabrics can be embossed?

A

Fabrics with thermoplastic properties such as polyester, polyamide

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19
Q

how is heatsetting finish done?

A

Fabric is stretched, creased, pleated etc into position before passing through a stenter machine, heating chamber, which sets the fabric into shape using the fabrics thermoplastic properties. When the fabric cools, it retains it’s set size and shape.

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20
Q

what are the benefits of heat setting?

A

-makes pleats and creases permanent- prevents the consumer from having to iron them into place continously
-prevents the fabric from shrinking
-prevents the fabric from creasing

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21
Q

what are the reasons for using a heat setting fabric finish?

A

-fibres such as cotton and viscose crease easily
-some products need to be easier to care for or able to hold pleats/creases

22
Q

how is stone and sand washing fabric finish done?

A
  • finished garments or lengths of fabric are placed in industrial washing machines filled with sand or stones, or are sprayed with sand and stones
23
Q

what appearance does stone and sand washing give a fabric?

A

-adds a worn, aged appearance to fabrics
-gives a soft, flexible handle to fabrics

24
Q

what are the disadvantages of stone and sand washing?

A

-incredibly dangerous and harmful to factory workers who breath in the fumes caused by stone and sand washing causing respiratory issues- unethical process

25
Q

what are the 5 mechanical fabric finishes?

A

-calendaring
-stone/sand washing
-embossing
-brushing
-heat setting

26
Q

chemical finishes…

A

improve the aesthetic qualities and functionality of fabrics by modifying the fabrics structure or surface. chemical finishes are wet processes involving chemicals.

27
Q

what does a flame retardancy finish do?

A

makes a fabric burn more slowly or less easily to catch on fire by applying a flame retardant finish

28
Q

how is a flame retardancy finish applied?

A

the chemicals used for flame retardancy finish- proban or pryovatex modify the fibres by trapping a polymer within the fibres, suppressing the chemical reactions in the flame or ability to ignite

29
Q

what are the two most common water resistant finishes?

A

-Scotchguard- silicon based and is used on furnishing fabrics and carpets
-Teflon- PTFE based, and doesn’t affect the breathability or handle of fabrics

30
Q

what are water resistant finishes used for?

A

-creating a protective barrier against stain and liquids that sit on the surface of the fabric rather than sink in

31
Q

what is non iron/easy-care fabric finish used for?

A

fabrics that crease easily during wear and laundering- such as fabrics made from cellulosic fibres

32
Q

how is non iron/easy care fabric finish done?

A

Synthetic resin based chemicals are used to modify the fibres and prevent shrinkage. The treated fabric is held in tension in a heat chamber to cure and seal the finish

33
Q

what is a moth proofing fabric finish?

A

a fabric finish which prevents the attraction of moths on certain fabrics (e.g wool)- the presence of sulphur molecules in wool fibres attracts moths.

34
Q

how is moth proofing fabric finish done?

A

by impregnating the wool fibres with mitin or dielmoth which makes the wool fibres inedible to moths without damaging the fabric

35
Q

what is pilling?

A

when friction causes the forming of small balls of fibres on the surface of the fabric

36
Q

how is an anti-pilling fabric finish done?

A

polymers or solvents can be used to prevent fibre movement from happening as quickly and can help bind fibres into the surface of a fabric to stop them becoming loose

37
Q

what is a hygienic fabric finish used for?

A

inhibiting the growth of microbes which means odours, infections, and dust mites can be controlled.

38
Q

how is a hygienic fabric finish done?

A

anti-microbial chemicals are added directly into the spinning solution or they can be applied to the surface of a fabric.

anti-bacterial finishes such as chitosan are useful for sensitive skin and allergies. it can be applied as a surface finish or as a micro-encapsulated finish.

39
Q

what is mercerisation?

A

a chemical treatment to make cotton shinier, stronger and more absorbent, improving dye uptake

40
Q

how is a mercerisation fabric finish done?

A

cotton yarn or fabric is treated in a concentrated solution of caustic soda (sodium hydroxide). the chemicals cause the cotton fibres to swell and become smoother and more rounded.

41
Q

what are some trade names for hygienic fabric finish?

A

-chitozan
-permafresh
-bioguard
-amicor

42
Q

what is the appearance caused by a mercerisation fabric finish?

A

-makes cotton shinier, stronger, more absorbent, improves dye uptake.

43
Q

what are the 8 chemical fabric finishes?

A

-flame retardancy
-anti-piling
-mercerisation
-non-iron/easy care
-hygienic
-water resistance
-moth proofing
-shrink resistance

44
Q

what are laminated fabrics made up of?

A

two or more very thin layers of fabric. the layers are held together with adhesives or fused together by heat setting if thermoplastic fabrics are used

45
Q

what is a Gore-tex membrane laminated between?

A

-between a high performance fabric and a softer inner lining layer.

46
Q

what is the Gore-tex membrane like?

A

very thin, non-woven PTFE filled with billions of microscopic holes- the holes are too small for rainwater to pass through and the membrane acts as a wind barrier, making it waterproof and windproof.

Gore-tex is breathable as the holes are big enough to let water molecules from perspiration pass through.

47
Q

what are the properties of Gore-tex?

A

-breathable
-windproof
-waterproof
-lightweight
-compact

48
Q

what is gore-tex used in?

A

-outdoor clothing
-waterproof jackets
-sports wear

49
Q

what are the properties of Sympatex?

A

-waterproof
-windproof
-breathable
-hydrophilic (water-attracting)

50
Q

what does the sympatex membrane do?

A

the membrane is poreless and hydrophilic (water-attracting). the membrane attracts, draws and holds moisture away from the body to transport it to the outside so that it can evaporate. the poreless membrane structure prevents rain from getting through.

51
Q

what are the two types of laminated membranes?

A

-Gore-Tex
-sympatex

52
Q

what is the effect of mercerisation?

A

Mercerisation involves treating cotton fibres in caustic soda- this changes the cotton fibre from a ribbon-twisted like form to a more circular cross section. this adds strength and lustre to cotton, and it also means that cotton will be better at absorbing dyes.