Last Test

Question 1

Colour fastness in light

Answer 1

This test assesses fabrics in artificial light and normal light to see how fabric colour reacts

Question 2

Explain why light testing is taken out?

Answer 2

Due to light “yellowing,” fabrics its is key to see what correct dye and accurate prediction of properties is very essential

Question 3

What are the variables that are important to light colour fastness

Answer 3

Product end use - meaning that how long it will be exposed outdoors

Country - how long will it be in the sun for and where

Quality of the fabric and dye - the higher the cost the more high quality

Question 4

Why do we Test laundering

Answer 4

Because the end use customers will wash there garments

Question 5

What is dry cleaning testing for colourfastness

Answer 5

Normal dry cleaning and the rubbing of organic solvents which is called spot cleansing this tests how colour reacts to this

Question 6

Dry cleaning explain?

Answer 6

Some fabrics cannot be laundered due to certain linings within the product which may results into dimensional instability thus dry cleaning is best

Question 7

Carpet cleaning?

Answer 7

Carpets must be cleaned occasionally when carpets are in production they are tested for colourfastness due to people clean them and spot clean them with different types of chemicals

Question 8

Colour fastness to aqueous agencies

Answer 8

Testing how fabrics react to with different liquids that will come in contact with the fabric eg - seawater, chlorine, acid and steaming

Question 9

Colour fastness with atmosphere contaminants

Answer 9

Assessing colour fastness to nitrogen oxides and nitrogen oxides at high humidities and °c. This tests is for working clothes mostly

Question 10

Colour fasting to bleaching agents

Answer 10

This assesses the fastness of various textiles have to bleaching agents. A successful bleaching is suppose to have low colour difference

Question 11

Test for laundering BS EN 20105 A02

Answer 11

Two samples are taken one is left untreated and untouched while the other is tested for colour fastness with a standard method after the test I’d completed there is a grey scale witch helps compare the two fabrics changes of colour (colour loss)

Question 12

Test BS EN 20105 A03

Answer 12

Two multi fibre strips are tested. One is left untouched and one is treated for colour fastness. In the end the two specimens are again compared on they grey scale (colour gain)

Question 13

Explain the grey scale

Answer 13

There are two grey scales one for colour loss and colour gain
They are rated 1,2,3,4,5

Question 14

The two factors that affects colour chamber in all testing

Answer 14

The Colourant - breaks down inside the fibres and therefore becomes colourless or changes colour

The bond holding the fibre - Colourant holding fibre breaks meaning Colourant becomes detached from fibre

Question 15

Colour fastness to heat treatments

Answer 15

Dry heat and steam pleating, both common, colours chamber and often temporary disappear due more to wet heat

Question 16

Colour fastness to vulcanising

Answer 16

When the rubber causes change or loss in colour mostly in elastane production

Question 17

What is vulcanising

Answer 17

Heat treatment with sulphur given a natural rubber to improve its strength and elasticity

Question 18

Colour fastness to miscellaneous agencies

Answer 18

This is when colour loss happens due to wear of the garment

Question 19

Name carbonising treatments

Answer 19

Carbonising treatment - removes impurities from wool
Mercerising treatment - to improve quality of cotton
De gumming - for silk to remove rubbish
Formaldehyde - crease resistance (affects colour)
PVC coating - colour migrates to coating

Question 20

Colour change due to abrasion wear

Answer 20

Happens when a textile is worn a lot

Question 21

Factors that affect garments to fade when worn are?

Answer 21

Loss of colour instability - chased when dyes are poorly bonded with the fibres that they rub off on other textiles leaving stains

Loss of colour due to insufficient dye penetration - when dye only sticks to the top of the fibres and not deep down inside the fibres causing it surface and rub off

Loss of colour due to structure change - carpets velvet and brushed cotton have pile or nap which is a top layer which after sometime can be abraded down and loss of colour and vibrancy I

Question 22

What are the three types of colour change

Answer 22

Depth - a sample may appear lighter or darker

Hue- sample may change slightly eg - red to orange or pink

Brightness - a fabric may seem brighter or duller

Question 23

Factors that affect the OVERALL colourfastness

Answer 23

The chemical structure - some colourants are naturally resistant to some agents due to there chemical and physical structure meaning that dyes breakdown fibres and fibre may a sort and lighten

The state of the Colourant in the fibre - cellulosic direct bonds are easily broken meaning fairy poor colour fastness, whereas if it’s reflective Colourant it is less fading

The amount of Colourant in the fibre - the more deep the Colourant is the less the colour will fade

The fibre - related to chemical and physical structure of the fibre different structure react differently to different dyes

Foreign substances - substances other than dyes may be present such as moisture, delusterants, finishings all of these reduce the bonds thus sometimes making the dye patchyj

Question 24

What are the aims and why is colour fastness tested?

Answer 24

Colour fastness is tested in order to see how different fabrics react with different dyes and different factors this can help inform customers how to handle the garment in the end use