28010401 textile auxiliaries non surfactant auxiliaries 01
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Non-surfactant
auxilaries andapplications
Wirote Sarakarnkosol
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Non-surfactant auxiliaries
: Classification Electrolyte pH control
Enzyme Reducing and Oxidising agents Sequestering agent Thickener and Migration inhibitor Hydrotropic agents Fastness improving agents
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Electrolyte
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Electrolyte
NaCl and Na2SO4 are commonly used.
Increase the adsorption of Reactive and
Direct dyes on cellulose. (Also for leuco Vat
and Sulphur dyes)
Promote aggregation of soluble dyes.
NaCl gave stronger effect than Na2SO4.
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Electrolyte
Decrease the adsorption of Anionic dyes
on PA and WO.
Kosmotropes increase hydrophobic increase dye adsorption
Chaotropes decrease hydrophobic decrease dye adsorption
NaCl gave more decreasing
the adsorption of anionic dyes
on PA than Na2SO4 !!
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Electrolyte:: Equilibrium adsorption isotherm at 34oC and rate of dyeing at 40oC for CI Direct Blue 1 on viscose in
the presence of electrolyte singly and binary mixture
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Electrolyte:: Fixation of CI Reactive Red 180 with various concentrations of Group IA chlorides
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Electrolyte:: Fixation of CI Reactive Red 180 with various concentrations of potassium salts of dicarboxylic acids
K oxalate
K tartrate
K phthalate
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Electrolyte
: Ecological approach High salt loading is indesirable in waste-
water.
Na2SO
4causes corrosion of concrete
pipes.
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pH control :
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pH control :
3 differents technique1. Maintenance of a high degree of acidity or alkalinity
2. Control pH within fairly narrow tolerance mainly in the
near-neutral region (pH 4-9)3. Gradual shifting of the pH as dyeing proceeds
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pH control
: Maintenance of a high degree of acidity or alkalinity Easy to control
Acid region use in application oflevelling
acid and 1:1 metal complex dyes to PAand WO.
Alkali region use in reactive, sulphurorvat
dyes to CEL.
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pH control:pH value of some common acid in distilled water.
Normality 2 N 1 N 0.1 N x N 0.01 N 0.001 N
Material
Hydrochloric acid g/l - 36.5 3.65 1 g/l 0.37 0.037
HCl pH - 0.11 1.08 1.61 2.00 3.00
Sulphuric acid g/l - 49.0 4.9 1 g/l 0.49 0.049
H2SO
4pH - 0.24 1.17 1.79 2.05 3.00
Formic acid g/l 92.0 46.0 4.60 1 g/l 0.46 0.046
HCOOH pH 1.61 1.79 2.32 2.76 2.85 3.42
Lactic acid g/l 180.0 90.0 9.00 1 g/l 0.90 0.090
C3H
6O
3pH 1.78 1.97 2.43 2.94 2.95 3.50
Acetic acid g/l 120.0 60.0 6.00 1 g/l 0.60 0.060
CH3COOH pH 2.18 2.40 2.87 3.27 3.37 3.89
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pH control:pH value of some common base with concentration.
Normality 2 N 1 N 0.1 N x N 0.01 N 0.001 N
Material
T.S.P.P. g/l - 83.0 8.30 1 g/l 0.83 0.083
Na4
P4
O7
pH - 10.50 10.15 9.35 9.25 9.01
Sodium carbonate g/l 106.0 53.0 5.30 1 g/l 0.53 0.053
Na2CO
3pH 11.60 11.50 11.00 10.30 10.00 9.80
Ammonia g/l 34.0 17.0 1.70 1 g/l 0.17 0.017
NH4OH pH 11.72 11.59 11.16 11.00 10.64 10.15
Sodium phosphate g/l 98.6 49.3 4.93 1 g/l 0.49 0.049
Na3PO
4pH 12.8 12.30 11.40 11.20 11.10 10.95
Sodium hydroxide g/l - 40.0 4.00 1 g/l 0.40 0.040
NaOH pH - 13.93 12.98 12.38 12.00 11.00
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pH control : Near-neutral region (pH 4-9)
Very difficult to control.
pH of pure water7.47 at 0oC, 7.00 at 24oC and
6.13 at 100oC. Use in Milling acid and 1:2 metal complex dyes
on PA and WO., Basic dyes on PAN and
Disperse dyes on PES, PA, PAN.
Precise control with buffer.
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pH control : Buffer
Buffers are generally based on
combinations ofweak acid + its base salt
orweak base + its acid salt Most common buffer is acetic acid/sodium
acetate (pH range 3.8 5.8) Low cost
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Buffer : Phosphate buffer
More cost than acetate
buffer
More resistant totemperature induced
change
Buffering region at pH
2.5-3.5, pH 6-8 and pH10.5-11
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Buffer : Others
Pyrophosphoric acid (H4P
2O
7) and its salts
(pH 39)
Orthoboric acid (H3BO3), sodium tetraborate(borax Na
2B
4O
7) and sodium hydroxide
(pH 8.110.1) Citric acid and sodium hydroxide (pH 2.16.4) Sodium carbonate and sodium bicarbonate
(pH 9.311.3).
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pH control : Shifting of the pH
Acid shift region use fornon-migrating anionic
dyes on WO or PA.
Ammonium salts is the conventional system foracid shifting.
Alkali shift region use forreactive dyes on CEL.
Sodium salts of volatile acid is the conventionalsystem foralkaline shifting.
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Acid shifting : Ammonium salts
Ammonium sulfate generally used for
dyeing milling acid dyes on PA and WO.
Can be used only open system.
Acid liberate
Volatile to atmosphere
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Acid shifting : Hydrolysable ester
Can be used alone or mix with alkali for
higher starting pH.
Can be used in closed system
High cost
Such as Ethylactate
Lactic acid
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Acid shifting : Hydrolysable ester
Diethyl tatrate 2-Hydroxyethyl chloroacetate
Acid part
Acid part
Alcohol part
Alcohol part
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Acid shifting : Lactone
-butyrolactone
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Alkaline shifting :
Salt of weak acid
Alkali liberate
Sodium formate and Sodium bicarbonate are also used
forreactive dyes on CEL printing.
Sodium acetate
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Enzyme :
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Enzyme :
Biocatalyst foraccelerating the reaction
-amylase use fordesizing process
Catalase forremoving residual H2O
2after
bleaching
Cellulase forbiofinishing of denim
Etc.
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Amylase enzyme for desizing
Convert starch to water-soluble product
Non-ionic wetting agent should be combine used
Temperature range cover 20 115
o
C:Prefer > 70oC (gelatinous point of starch)
pH range cover 5.5 9 : Prefer pH 7 8 (conditionfor degraded product solubilisation)
Salt and Hardness maybe require. Detect residual starch with Iodine solution
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Amylase enzyme for desizing
Mode of action of enzymatic degradation : by SDC
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Amylase enzyme for desizing
Optimum conditions for enzymatic desizing : by SDC
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Amylase enzyme for desizingTest for degree of desizing (TEGEWA scale) : by SDC
TEKEWA Rating 1 TEKEWA Rating 7
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Catalase :
Remove residual H2O
2to water and
oxygen.
Activity range pH about 5-9
Activity range temperature 50-55oC
Do not destroy the dye molecules.
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Catalase :Hydrogenperoxide removal efficiencyLiquor condition 0.1 g/l 50% Hydrogenperoxide
0.1 g/l Organic stabilizing agent
X g/l Product test
Procedure : Keep the dye liquor at XC for 10 min. and follow dyeing with H2O2 sensitive reactive dyes
Further dyeing : 1 % Sensitive Reactive Blue dye.
40 g/l Common salt
20 g/l Soda Ash60 min at 60C LR 10:1
Material: knitted cotton
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Cellulase
Can convert Cellulose to soluble product
Partially or wholly replacement of Pumice stone
abrasion on cotton denim fabric. Saving in time and labour, much less fabric
abrasion and no debris.
Devided to Neutral andAcid cellulase
Contain endocellulase, exocellulase orbeta-
glucanases
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Cellulase :Dissolution of the cellulose
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Cellulase : Denim finishing
Denim is cotton twill-weave fabric with a dyedwarp with INDIGO and raw white weft.
Acid cellulases (pH 4.55.5 ; 4555oC) give high
aggressive action on cotton which use shortertime but backstaining.
Neutral cellulases (pH 68 ; 5060oC)have lessaggressive action but less or no backstaining.
Terminated with inactivating, by raising the pH to10 or by increasing the temperature to75oC for1015 minutes.
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Reducing agent & Oxidising agent
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Reducing agent & Oxidising agent
Decoloration of material- Bleaching- Stripping
Redox inhibitor- Reduction inhibitor- Antioxidant
Coloration assistance- Reducing agent for Vat & Sulphur dyes- Re-oxidising agent for Vat & Sulphur dyes
3 ACTIONS
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Reduction of Vat dyes
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Reducing agent : Vat dyes assistantReduction potentials of various reducing agents measured as 5 g/l solutions in
15 ml/l caustic soda 38o
B at 60o
C
- Vat dyes have reduction potentials in aqueous media from770 to 1000 mV
the majority 900 to 950.
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Reduction of Sulphur dyes
Sulphur dyes
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Reducing agent : Sulphur dyes assistantReduction potentials of various reducing agents measured as 5 g/l solutions in
15 ml/l caustic soda 38o
B at 50o
C
Sulphur dyes have average only about600 mV
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Reduction clearing of Disperse azo
dyes
CI Disperse Orange 5
Example
N N
Cl
Cl
O2N N
CH3
CH2CH2OH
4H
NH2
Cl
Cl
O2N H2N N
CH3
CH2CH2OH
+
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Reducing agent :Fastness of black polyester dyeings after various reduction clearing
treatments
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Reducing agent : Sodium dithionite
/Hydros/Sodium hydrosulphite Most important reducing system for the batchwise application of vat
dyes in a solution of sodium hydroxide.
Forsulphur dyes, the process is difficult to control and may bedestroyed through OVER-REDUCTION.
But effective with CI Solubilised Sulphurand sulphurised vat dyes.
Reduction clearing forDisperse dyes.
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Reducing agent : Sodium dithionite
/Hydros/Sodium hydrosulphiteReduction reaction of hydros with Vat dyes
Reduction reaction of hydros with atmosphere
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Reducing agent : Sodium dithionite
Environmental problems Can produce sulphite and sulphate.
Sulphite can be oxidised easily to sulphate
High concentrations of sulphate can cause
damage to unprotected concrete pipes.
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Reducing agent : Sodium sulphide
and Sodium hydrogen sulphide Most widely used for Sulphur dyes
At least 12 g/l sodium sulphide is required to
dissolve the water-insoluble CI Sulphur dyes Sodium hydrogen sulphide is use 0.6 times of
sodium sulphide but necessary to add alkali (10
g sodium hydroxide or 5 g sodium carbonate per
7 g sodium hydrogen sulphide)
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Reducing agent : Sulphide
Environmental problems. Toxicity ofhydrogen sulphide. Odour threshold being 0.035 0.14 mg/m3
Unpleasant odours (pH < 9) Neutralisation or acidification can occurgaseous
hydrogen sulphide. Corrosion of the effluent drainage system.
Damage to the treatment works and the oftenassociated high pH.
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Reducing agent :Thiourea dioxide/
Formamidine sulphinic acid Powerful reducing agent for vat dyes.
Lower MW than sodium dithionite.
Lower sulphite and sulphate load. More stable than sodium dithionite.
Cause over-reduction of indanthrone vat dyes.
Glucose or sodium nitrite cant stabilise. Very good for reductive colorant stripping.
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Reducing agent :Thiourea dioxide/
Formamidine sulphinic acid Formamidine-sulphinate in alkaline media
is more readily oxidised than dithionite.
Low water solubility. Not suitable for continuous process.
Thiourea dioxide Sodium formamidinesulphinate Sodium hydrogen sulphoxylate
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Reducing agent : Sodium
formaldehyde-sulphoxylate Know as Rongalite C orFormulsol G
Produce from Sodium dithionite with
formaldehyde More stable than dithionite at lower
temperatures
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Reducing agent : Sodium
formaldehyde-sulphoxylate Can be used to prepare stable pad liquors
and print pastes.
At higher temperatures, they are capableofrapid reduction of vat dyes.
Used first in conventional steam fixation of
vat prints.
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Reducing agent :
Other sulphoxylates Sodium acetaldehyde is suitable for flash-ageing
process.
Zinc formaldehyde sulphoxylate :- Mono zinc : Water soluble
- Di zinc : Water insoluble
Calcium formaldehyde sulphoxylate is insolublein water which low tendency to haloing
Mono Zinc formaldehyde sulfoxylateSod. acetaldehyde sulfoxylate Calcium formaldehyde sulfoxylate
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Reducing agent : Hydroxyacetone
Sulphur-free and biodegradable
Used for vat, sulphur and indigo dyes with
high concentrations of NaOH Does not over-reduction of indanthrone.
Give different shades with carbazole dyes,
compared with sodium dithionite
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Reducing agent : Glucose
Characteristic odour preferable than odour ofalkaline sulphide bath.
High alkali concentration is required. Minimum dyeing temperature of 9095oC being
necessary. High COD level in the effluent. A lot of by-product ; losing its reducing action. Should mix with Hydros forhigher efficiency
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Reducing agent :
Dithionite/glucose system
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Reducing agent :
Dithionite/glucose system Potential slightly lower than that of dithionite
alone, although glucose has the lowest potential.
Without the risk of over-reduction. Optimal colour yield and good reproducibility
Other glucose binary systems, including
hydroxy- acetone or sodium formaldehyde-
sulphoxylate as stabiliser gave similar results.
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Reducing agent : Others
2-Mercaptoethanol
Sodium hydrogen sulphite
Iron Triethanolamine complex
Iron Gluconic acid complex
etc.
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Reducing agent : Summary of advantages anddisadvantages of the three most important types reducing
agent for indigo, vat or sulphur dyeingSodium dithionite
Advantages
(1) Sufficient reduction potential for vat, sulphur or indigo dyeing(2) Good stability of leuco vat dyebaths
Disadvantages
(1) Waste water loading; inhibits biological degradation and leads
to a greater oxygen demand
(2) Can cause over-reduction at higher temperatures
(3) Special safe storage facility required
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Reducing agent : Summary of advantages anddisadvantages of the three most important types reducing
agent for indigo, vat or sulphur dyeingSulphinic acid derivatives
Advantages
(1) Sufficient reduction potential for vat, sulphur or indigo dyeing.(2) Especially suitable for high-temperature dyeing methods.
(3) Good resistance to oxidation by air.
Disadvantages
(1)As fordithionite disadvantage (1)
(2) Potentially temperature-dependent.
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Reducing agent : Summary of advantages anddisadvantages of the three most important types reducing
agent for indigo, vat or sulphur dyeingHydroxyacetone
Advantages
(1) Biologically degradable(2) Ease of dosing in liquid form
(3) Very good stability to storage
Disadvantages
(1) Does not reach full reduction potential and thus mainly
suitable for indigo and sulphur dyes
(2) Persistent odour
(3) Limited commercial production
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Oxidising agents : H2O2
Use forbleaching on Cotton and other CELs.
Can use as re-oxidising agent for vat dye and
sulphur dyes (easy but low washing fastness) Environmentally friendly (Very low AOX values)
Peroxide bath do not corrosive
Can be used both exhaustion and continuous
Give a good whiteness even without prior
scouring
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Oxidising agents : H2O2
Fiberdamage (occur by free radical formation
especially in the present iron or copper)
Quality of whiteness (Less attractive tone) Cost-effectiveness (AOX-containing effuent are
omitted)
- 2 times of hypochlorite bleaching in batchwise process
- 6 times of hypochlorite bleaching in continuous process
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Oxidising agents : H2O2
:Effect of pH in bleaching
Optimum
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Oxidising agents for bleaching :
H2O
2:Mechanism of bleaching and fibre damage
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Oxidising agents : H2O2
:Effect of Fe(III) concentration on rate of decomposition
2.9 g/l H2O2, Sodium Silicate 5 g/l, Magnesium Sulphate 0.2 g/l 95o
C, pH 12 (Absence of substrate)
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Schematic diagram of catalytic
damage occurrence
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Oxidising agents : H2O2
: Desizing of PVA
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Oxidising agent :
Sodium hypochlorite Most environmentally damaging of all bleaching agent
with regard to AOX values. May even be banned insome countries.
Bleached goods are prone to subsequent yellowing onstorage. Substrate must be scoured before bleaching. Stock solutions of sodium hypochlorite are unstable and
must always be chemically analysed before use. Hypochlorite bleaching can not combine with some
FWAs and dyestuff.
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Oxidising agent :
Sodium hypochlorite Economical attractiveness
Lower risk of catalytic fibre damage,
although some chemical damage canoccur depending on temperature and pH
Powerful bleaching action.
High attractive whiteness (Bluish white)
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Oxidising agent :
Sodium hypochloriteEffect of pH on the composition of sodium hypochlorite solutions
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Oxidising agent :
Sodium hypochloriteAfter bleaching with hypochlorite it is
always necessary to remove residual
chlorine present call Antichlor Bisulphite and hydrogen peroxide are
generally used for antichlor
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Oxidising agent : Sodium chlorite
Lower AOX values than hypochlorite. Generally carried out underacidic conditions. (different
from peroxide and hypochlorite)
Risk of chemical damage is low. Minimal scouring action in acidic bleach results in lower
weight losses hence good sewability Least sensitive to accelerated damage by metallic
contamination useful for synthetic fibres and particularly important foracrylic fibres.
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Oxidising agent : Sodium chlorite
Toxic and unpleasant chlorine dioxide vapour
can be liberated.
Highly corrosive. No rapid chlorite bleaching process is available.
Bleached goods gave lower absorbency.
Some dyes and FBAs are destroyed by chlorite
bleaching
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Oxidising agent : Sodium chlorite
:Effect of pH on the composition of sodium chlorite solutions
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Oxidising agent : Peracetic acid
Peracetic acids can be effective oxidative
bleaching agents and, at least potentially,
offer an alternative to the environmentallysensitive chlorine bleaches.
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Oxidising agent : Dichromate and
chromate salts.
Sodium and Potassium salts are generally used.
Use combine with acetic acid (pH 4.5-5.5) for re-
oxidising sulphur dyes Gave the harsher handle and less hydrophilic of
dyed fabric
Can not use in yarn dyes because its decrease
the winding property of yarn.
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Oxidising agent : Dichromate and
chromate salts.
Ifcombine with Coppersalt, Light fastness is
improved
Provide high washing and rubbing fastness. Environmental problem due to Cr3+
Low cost
Sometimes use as antireduction for disperse
dyes on T/C.
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Oxidising agent : Iodate salts
Potassium iodate is generally used.
For re-oxidise of sulphur dyes, no harsherhandle and
high rubbing fastness.
Use combine with Lactic or Acetic acid (pH 3.5-5)
Not Formic acid!!
Very high cost.
Maybe use as anti-reduction for disperse dyes on T/C.
O
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Oxidising agent :
Sodium m-nitrobenzene sulphonate
Use as anti-reduction for reactive, direct
and acid dyes.
Protect the reduction of azo group via heatorunfavorite condition.
Can re-oxidise Vat and Sulphur dyes.
NO2
SO3Na
2H
NH2
SO3Na
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