main parameters that influence discontinuous traditional ... · sodium carbonate g/l 2 hydrogen...
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Main parameters that influence discontinuous traditional Peroxide bleaching
v reaction time v temperature v pH
High temperature and pH can cause a quick and uncontrolled Peroxide decomposition with consequent decrease of the degree of polymerization of the fabric, due to the action of free radicals.
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EASYWHITE BLEACHING SYSTEM
Peroxide activator - EASYWHITE ACTIV v accelerates the bleaching rate of cellulose and blends (linen,
viscose, bamboo) at lower temperatures and milder alkaline conditions
v accelerates the bleaching rate without being consumed; it repeats the same reaction several times, that is why only low quantities are required
Multifunctional product – EASYWHITE AC/JET v offers wetting/detergent/sequestering properties
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Parameters taken into consideration during tests pH
v an excessively low pH provokes poor hydrophily and an insufficient degree of whiteness
v an excessively high pH initiates the decomposition of the activator and Hydrogen Peroxide
The best workable pH is between 10 – 11.5 Type and concentration of wetting/detergent agent
v it has to reduce the surface tension between the fabric and the bath
v it must have a quick wetting effect v it must improve the soaping of wax and fat present on the fibre v it must be a non-foaming product
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Parameters taken into consideration during tests Type and concentration of sequestering agent
Easywhite bleaching system does not provide the use of a stabilizer; the replacement of the stabilizer with a sequestering agent v is useful for the removal of metallic ions v forms a complex with the activator stabilizing itself
Not all the sequestering agents are able to form a complex with the activator
H2O2 quantity v according to the required whiteness degree 4 – 7 cc/l of Hydrogen
Peroxide 130 Vol. on cotton and 3 – 10 cc/l on viscose is required
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Parameters taken into consideration during tests
Activator quantity v in case of a lower pH, a increased quantity of activator is needed
Temperature and time v the Easywhite system allows bleaching of cellulose fibres at
temperatures which are 15 – 20°C lower compared to traditional systems
v the cotton bleaching can be done at 80°C and the viscose bleaching at 60 – 70°C
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Parameters taken into consideration during tests Influence of Easywhite Activ quantity on Peroxide residual
(on raw cotton at 80°C)
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10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30
time
%
higher concentration
medium concentration
lower concentration
Log. (higherconcentration)Potenza (higherconcentration)Potenza (higherconcentration)
Recipe1.5cc/lEasywhiteAC/JET2.5cc/lCausticSoda36Bè7.0cc/lHydrogenPeroxide130Vol.X.0cc/lEasywhiteActive
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Parameters taken into consideration during tests Influence of pH and Easywhite Activ on Berger whiteness degree
(on raw cotton at 80°C for 30 minutes)
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10,4 10,5 10,6 10,7 10,8 10,9 11 11,1 11,2
pH
Berg
er
without
0.8 cc/l Easywhite Activ
Recipe1.5cc/lEasywhiteAC/JET2.5cc/lCausticSoda36Bè7.0cc/lHydrogenPeroxide130Vol.
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TRADITIONAL RECIPE COMPARED TO EASYWHITE SYSTEM ON COTTON (ready for dyeing bleaching)
Standard Easywhite bleaching system
wetting/detergent agent cc/l 1 – 2 wetting/detergent/sequestering agent (Easywhite AC/JET) cc/l 1 – 1.5
stabilizer cc/l 0.4 – 0.7 Caustic Soda 36 Bè cc/l 2 – 2.5
Caustic Soda 36 Bè cc/l 3 – 4 Hydrogen Peroxide 130 Vol. cc/l 4 – 7
Hydrogen Peroxide 130 Vol. cc/l 4 – 7 activator (Easywhite Activ)
cc/l 0.6 – 0.8
100°C for 30 minutes 80°C for 30 minutes
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TRADITIONAL RECIPE COMPARED TO EASYWHITE SYSTEM ON COTTON
STANDARD
30
40
50
60
70
80
90
100
110
0 10 20 30 40 50 60 70 80 90
Time (min.)
Tem
pera
ture
(°C)
products
overflow washing
neutralizationwashing
EASYWHITE bleaching system
30
40
50
60
70
80
90
100
110
0 10 20 30 40 50 60 70 80 90
Time (min.)
Tem
pera
ture
(°C)
products
overflow washing
neutralization
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Standard Easywhite bleaching system
wetting/detergent agent cc/l 1 wetting/detergent/sequestering agent (Easywhite AC/JET) cc/l 1
stabilizer cc/l 0.2 – 0.3 Sodium Carbonate g/l 1 – 1.5
Sodium Carbonate g/l 2 Hydrogen Peroxide 130 Vol. cc/l 1 – 3
Hydrogen Peroxide 130 Vol. cc/l 1 – 3 activator (Easywhite Activ)
cc/l 0.5 – 0.6
80°C for 20 minutes 60°C for 20 minutes
TRADITIONAL RECIPE COMPARED TO EASYWHITE SYSTEM ON THERMOFIXED VISCOSE/LYCRA
(ready for dyeing bleaching)
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TRADITIONAL RECIPE COMPARED TO EASYWHITE SYSTEM ON THERMOFIXED VISCOSE/LYCRA
STANDARD
30
40
50
60
70
80
90
100
110
0 10 20 30 40 50 60 70 80 90
Time (min.)
Tem
pera
ture
(°C)
products
overflow washing
neutralization
EASYWHITE bleaching system
30
40
50
60
70
80
90
100
110
0 10 20 30 40 50 60 70 80 90
Time (min.)
Tem
pera
ture
(°C)
products
overflow washing
neutralization
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Advantages: v results of bleaching according to the standard, with minimum loss of
resistances v treatment flexibility v reduction of bleaching time (about 20%) v possibility of bleaching fibres sensitive to pH and temperature v reduction of water costs (about 15%) v reduction of energetic costs (about 5%) v increase of productivity v softer handle v low tendency to form creases v reduced pilling formation and fibre damage
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Further developments: cloro-free bleaching
Similar product to those used for bleaching can be used on denim to create an ageing effect. In combination with stone-wash and the use of stones, various effects can be obtained on indigo and indigo/sulphur dyed garments.
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PROCHIMICA NOVARESE S.p.A.
Via Marconi 21 - 28060 S. Pietro Mosezzo (NO) - Italy Tel. +39 0321 485511 - Fax +39 0321 468704
www.prochimicagroup.com for general information [email protected]
for technical assistance [email protected]