Textile chemistry

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Dyeing & Printing
Benchmark Assignment IV
On
Different Fastness Machines or Techniques
Submitted to: Ms. Ettishri Rajput Submitted by: Bittu Singh
Radhe Kumar
Shubham Singh

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1. AATCC Gray Scale
i. Gray Scale for Staining
 Used for evaluating staining on undyed textiles
 Consists pairs of white and gray color chips each representing a difference in
contrast, shade or strength
 Fastness grades of the scale are determined by a particular formula
 Fastness grade 5 – two identical white reference chips mounted side by side
having reflectance of not less than 85% - no difference in color contrast
 Fastness grade 4.5 – white chip paired with neutral gray chip
ii. Gray Scale for Color change
 Used in visual evaluation of changes in color of textiles resulting from
colorfastness tests
 Scale is placed along the edges of the two fabrics: tested and untested, and
visual differences are compared
 Specimen are viewed at an angle of 45 degrees in the Color Matching Cabinet
 Grade 5 – if there is no perceived difference between color or contrast

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2. Chromatic Transference Scale
 Used to visually evaluate color transfer or staining
 Consists of five hues from the Munsell Book of color : red, yellow, blue, green, purple
 Facilitates evaluation when used by a less experienced technician
 Rows are placed and aligned on white cardboard – every color shows a similar
gradation in depth in a vertical line
 A circular opening is provided in the color scale
 Fabric with transferred color should be placed behind the cardboard
 Fabric to be tested should be backed with a number of layers of clean test cloth
 The specimen is moved up and down until it most closely approximates chroma of
one of the chips
 If the specimen fall between two chips of varied intensity, a half step grade may be
assigned such as 1.5
 Grade 5 – no color transfer
 Grade 1 – greatest amount of color transfer
3. Spectrophotometer
 Photometric device that measures spectral transmittance and spectral reflectance
 Compares light leaving from the object with that incident on it at each wavelength
 Principle – amount of light absorbed by a medium is proportional to the concentration
of the absorbing material – gives the amount of color concentration
 Components :
 A stable source of radiant energy

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 A wavelength selector to isolate a desired wavelength from the source
 Transparent container for the sample
 A radiation detector to convert the radiant energy received to a measurable
signal
 A readout device that displays signal from the detector
 Procedure: It is set to a level of maximum light absorption, light absorbance is
measured, a standard curve of Absorbance vs. Concentration is plotted.
4. Ozone Fading
 Determines the resistance of color on textile material due to the action of ozone
present in atmosphere
 Primarily applied on textile materials which has been dyed with indigo dyes and
bleached materials which are treated with optical brightener
 Radiations emitted by light sources used in garment stores also contain fair amount
of ozone
 Ozone fading – influenced by temperature and moisture content
 Principle : Sample is exposed in a chamber generating ozone at a specified ppm for
one or two cycles and then compared for yellowness

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 Denim samples – exposed for two cycles, white – exposed for one cycle
5. Perspirometer
 To determine color fastness of dyed or printed fabric against perspiration
 Fabric sample is exposed to action of both the alkaline and acidic reagents
 Sample is in contact with undyed fabrics and placed between plastic plates under a
fixed load inside an oven maintained at 370 degree Celsius
 Components – made of stainless steel and finished in black enamel paint – corrosion
resistant
 Can also be used for testing color fastness against sea-water and water

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 Color fastness to perspiration should be at least level 3 or 4
 Specially applied for sportswear and heavy dresses
 Level 3 or 4 not desired when fabric is light-colored or is a blend with more than 20% silk
 Comparison of test specimen is done using gray-scales
 First sample – solution of pH 8 – liquor ratio of 20:1 – time allotted 30 minutes at room
temperature
 Second sample – solution of pH 5.5
 Apparatus – in oven for 4 hours at 37 degree Celsius
 Samples to be dried at temperature not exceeding 6- degree Celsius
6. Cuprammonium fluidity test :
 It is a method for determining the fluidity of lignified fibers
 To evaluate chemical degradation of cotton cellulose during scouring, bleaching etc.
 Pyrogallol enables the solution to be filtered in the presence of air before determining
the fluidity
 Insoluble residue is weighed after drying to calculate concentration of dissolved dry
material
 Fluidity gives an estimate of the degree of chemical degradation caused by agencies
such as heat, light, acid, bleaching solutions etc.
 Amount of insoluble matter decreases with increasing degradation
 Conditional cotton sample is exactly weighed and dissolved in Cuprammonium
Hydroxide solution
 Measurement is done on a calibrated viscometer at a specific temperature
 Fluidity values between 5-8 are considered to be satisfactory for normal bleached
fabric
 Preparation of solution per 1000 ml : should contain 235-240 grams of Ammonia(NH3)
& 14.9-15.1 grams of Copper – satisfactory for cellulosic fibres

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7. Blue Wool standards
 Measures and calibrates the permanence of coloring dyes
 Uses – In printing industry as a measure of lightfastness of ink colorants - In polymer
industry for measurement of pigment and color stability
 Two identical samples are taken – one is placed in the dark and the other is placed in
equivalent of sunlight for a 3-month period – amount of fading is then measured by
comparison
 Rating between 0 and 8 is awarded – 0 denotes extremely poor colorfastness – 8 when
no change in color
 General ratings :
 Apparel – 4
 Furnishings – 6
 Polymer materials – 7
 Fading kits – consist of 8 swatches of blue wool dyed to various levels – also consist
of 8 strips of wool mounted side by side on a small card – each strip is colored with a
blue dye that fades after exposure to a known amount of light
 Dyes – two to three times longer to begin fading as the next lower reference
 Reference1 – will begin to fade in 3 hours to 3 days
 Reference 3 – will begin to fade in 5 days to 2 weeks
 Reference 6 – will begin to fade in 6 to 16 weeks
 Reference 8 – will begin to fade in 6 to 15 months

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The following table gives exact match between the 8 Blue Wool standards & 5 ASTM
lightfastness categories.
Blue Wool standard ASTM category Description
8 900 Excellent – pigment remains unchanged
for more than 100 years of light exposure
7 300 Excellent – pigment remains unchanged
for more than 100 years of light exposure
6 100 Very good – pigment will remain
unchanged for more than 50 years
5 32 Fair – pigment will remain unchanged for
15-50 years
4 10 Fair – pigment will remain unchanged for
15-50 years
3 3.6 Poor – pigment will begin to fade in 2 to 15
years
2 1.3 Poor – pigment will begin to fade in 2 to 15
years
1 0.4 Very poor – pigment begins to fade in 2
years or even less
8. Laundromat
 For determining color-fastness of textile materials to washing
 Colorfastness to washing – resistance of a material to change to any one of its color
characteristics when subjected to washing
 Specimen with an attached adjacent fabric is subjected to washing under specific
conditions – the extent of change in color is assessed and expressed in fastness
numbers

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 A 10X4 cm swatch of the colored fabric is taken and is sandwiched between two
adjacent fabric and stitched
 Solution for washing should be prepared to the required temperature of washing
 Liquor-material ratio is 50:1
 Soaping treatment of the specimen followed by rinsing in cold water – air-dry at a
temperature not exceeding 60 degree Celsius
 Change in color is evaluated with the help of Gray scales

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Different types of washing has been covered in the table below.
Method Washing
severity
Soap + Soda
in grams/liter
Time in
minutes
Temperature Steel balls
IS:687:79 Very mild like
hand wash
5 30 38-42 Nil
IS:3361:79 5 times more
severe than
method 1
5 45 48-52 Nil
IS:764:79 Mild washing 5+2 30 58-62 Nil
IS:765:79 Severe
washing
5+2 30 93-97 10
IS:3417:79 Severe
washing
5+2 240 93-97 10
9. Gas Fading
i. General Procedure
 The specimens are placed in the gas filled chamber for a particular time
along with the control fabric.
 The test is conducted at 140*F for approximately 2-3 hours.
 The relative humidity is normally kept low due to the heating of gases.
 Gas fading termination: when blue sample turns a specific purple color.

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ii. Test Procedure
 Place the specimen (2x4 inches) and control sample (2x2 inches) in the gas
fading chamber.
 Heat the chamber to about 140*F by using Bunsen burner.
 Leave the specimens in the chamber until the color changes from blue to
purple.
 Use the Gray scale to determine the color fastness rating.
iii. Procedure (emery method)
 Place the emery paper and the specimen on the tester.
 The pressure on the diaphragm is set to be 3 psi and place a 3 pound load
on the head.
 Start the tester and allow it to run for 100 continuous cycles.
 Remove the specimen and vacuum it an order to remove fiber and
abrading residue.

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 Hand rinse the specimen by bolting it between two white cotton fibre hand
iron at 300*F.
 Repeat the procedure for other specimen, using Gray scale find the colour
fastness.
10.Chlorine Fastness
i. Theory
 For evaluating colorfastness of washing of textiles done in presence of
chlorine
 The test standard carried out is ISO 105 E03.
 Chlorinated Pool water fastness is getting more importance
in towel industry for swimwear and also for yarn dyeing.
 Designed to evaluate the resistance to Chlorinated Pool Water of any
colored textile substrate.
 Test specimen is treated in diluted Chlorine solution under specified
conditions of available chlorine content, time and pH condition.

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ii. Apparatus
 Gyro wash
 Grey scale
 Color matching chamber
 Glass beaker
 Stainless steel container
 pH meter
iii. Reagent
 Distilled water or de-ionized water.
 NaOCl solution (100 gm/l, 50 gm/l, 20 gm/l of active chlorine at pH
7.5±0.05)
iv. Sample preparation
A textile material (Dyed Goods) sample should be cut at 10 cm into 4 cm.
v. Procedure
 Put the specimen into the steel containers and added in the sodium
hydrochloride solution with liquor ratio 1:100 based on the
appropriate concentration of active chlorine used.

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↓
 Close the container and put it inti the mechanical device (Gyro wash)
and agitate at 27±20C for 1 hour in darkness.
↓
 Remove the specimen from the container and squeeze it.
↓
 Dry the specimen by hanging it in air at room temperature in quiet
light.
11.Colour matching box
 Color Matching Cabinet booth is used for visual assessment of colour
under 6 standard lights and comes with doors.
 It is a color measuring instrument used for color-quality assurance in
industrial products
 Color Matching Cabinet, Light Box, is suitable for yarn, fabric dyeing
plant, and garment manufacturer and exporters.

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 Suitable for staining, change in color test by using grey scales during
color fastness test.
i. Features of Color Matching Cabinet
 Cabinet is made of Teakwood, Ply Board & Sun mica, with strict
adherence to international standards.
 Supplied with major tube lights & bulbs for quick and accurate colour
assessment.
 Fitted with Electronic/ballasts for instant start & power saving to
safeguard the expensive & sensitive tube lights & bulbs
 No warm-up, No flick, No heat emission, Elapsed Time displaying of
each light source.
ii. Colour Matching Cabinet Confirms with following international standards
 ISO 3664, BS 950, ASTM D 1729, DIN 6173
12.Crock meter – Crocking fastness
In order to determine the color fastness of dyed or printed textiles or leather, this
test is used for the determination of color fastness against rubbing, either under dry
or under wet conditions.

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i. Features of crock meter
 To determine the Color Fastness of textiles.
 The equipment consists of a counter.
 It is provided with a flat peg.
 It also consists of an operating handle.
 Tests the color fastness of the textile in a very accurate manner.
ii. Specification of Crock meter
 Diameter of the Rubbing Finger : 16 mm & 25 mm
 Load on the Finger : 9 N & 20 N
 Size of Crocking Cloth : (5 x 5) cms & (7 x7) cms
 Length of the Traverse : 100 ±5 mm
 Counter (Re-settable) : 4-Digit Counter
 Size of Test Specimen : 25 x 5 Cm
 Overall Dimension of the Unit : 600 (W) x 190 (D) x 200 (H) mm
 Net Weight of the Unit: 4 Kg. (9 lbs.)
 Construction : Cold-rolled steel
iii. Working principle of Crock meter
 The Crock meter consists of a rigid flat metallic platform on which the
test specimen can be held firmly and an abrading finger which rubs
against it under a specified load.
 The platform is fixed over the base of the equipment and lies in a
horizontal plane.
 The test specimen is held firmly over an abrasive paper which is pasted
on the upper face of the platform, with the help of two pins holding it
at both ends.
 The abrading finger has a flat circular rubbing face which is covered
with 4 piece of white abradant fabric during the test.
 The abradant fabrics picks up colour lost by the test specimen during
rubbing.

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 It is held over the finger with the help of a tapered ring.
 Motion to the finger is given through a reciprocating arm with runs
and two ball bearings to minimize friction and to apply a uniform load
on the finger.
 The arm is moved by a manually operated crank and connecting line.
The equipment is finished in dark metallic paint and bright chrome
plating to give it a corrosion resistant finish
13.Snag Testing
 Test for evaluation of snagging performance
 Suitable for a range of woven and knitted fabrics made from textured or
un-textured yarns, containing staple or continuous filaments
 Not suitable for open construction, heavy or stiff fabrics
 Snagging – a visible color contrast is visible between a snag and a fabric
that has no defects
 Snags – composed of different combinations of protrusions and distortions
 A snag is created when an object pulls, plucks, scratches or drugs a group
of fibres/yarns from normal pattern
 Fabric specimen in tubular form are placed on a cylindrical drum
 A mace(spiked ball) is allowed to bounce randomly against specimen
 Observed resistance to snagging is reported on a scale ranging No. 5(no
snagging) to No. 1(very severe snagging)
 Used to test snagging resistance of most apparel and home furnishing
fabrics
 Snagging resistance of a fabric should be tested before and after
laundering or dry-cleaning
 Procedure : all specimen are tested in standard atmospheric conditions –
specimen are inspected for any blemish – blemished specimen are
replaced with good and fresh specimen – a tubular specimen is placed
onto the felt-covered drum with its face outwards – mace is positioned to
allow freedom of movement over entire surface – counter is set for 600
revolutions – visual standards for evaluation are chosen

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Snag Testing machines