Garment Wet Processing

Presented byAart Geurtsen

Wet processing of

Cotton Fabric

China is the largest producer in the world.

Current estimate of world cotton production is about

25 millions tons per yearThis means 112 millions bales of 480 lb/heac.

The properties of the cotton fiber varies from the conditions and the area where cotton is produced.

X 1000 X 480 lb. bales X 1000 X 480 lb. bales

Source:Source: United States Department of AgricultureUnited States Department of Agriculture

Top 5 World Producers of Cotton(Year 2011)

15674

27000

3350010000

9000 China 33500

USA 27000

India 15674

Pakistan 10000

Brazil 9000

* * Bangladesh 66 XBangladesh 66 X

Preparation of the Cotton fabric

• Scour• Pre-Bleach• Prepare for dyeing

Scour

0.5% Triscour JET conc1.0% Soda ash2.0% Caustic Soda 50%

96°C for 30 minutes Rinse et neutralize

Option 1• The scouring removes all dirts & chemicals present on the fabric,

which could interfer with the pretreatment (cationisation) of the fabric.

• It helps to make the fabric more absorbant allowing, in the same time, a better diffusion of the chemicals used to pretreat or

cationise the fibre.

Pre-Bleach

142,150

Helps remove the oxidized oils and the yellow pigment in the cotton .This bleaching will help

to obtain pale shades and more brilliant colors.

0.5% Triscour JET conc (wetting + detergent)0.1% Tristabilizer Jet-5 ( H2O2 Stabilizer)2% Caustic Soda 50% (NaOH)4% Percoxide 50% (H2O2)

(Temperature of 96°C for approximately 30 minutes)

Note: For a white, we will add an optical brightener Tricoblanc BA 80% liquid.

0.8% - 1.0 % owg.

This operation of bleaching will be followed by a neutralization with acetic acid, as well as the neutralization of peroxide by a catalase enzyme, such as Triminox GH.

Option 2

Prepare for dyeing Jersey or Fleece

Applying lubricant

After pre-bleach, the cotton will need an application of a polyethylene emultion and/or fatty acid in order to facilitate

the operations of napping or cut and sew.

This softener-lubricant is very easy to remove with a light Scouring, before carrying out the dyeing.

This operation is usually made by nip padderThis operation is usually made by nip padderwith:with:

30 gr. liter of 30 gr. liter of Tricosoft MSGTricosoft MSG

Dyeing process with pigments

• Scouring• Cationic pretreatment• Dyeing• Softener application

First Step prior to Garment Dying In some cases the presence of hand modifiers, could

make the fibre practically hydrophobic

Good scouring is a must

0.5 gr./l. Triscour JET conc

1.0 gr./l. Sodium Carbonate 2.0 gr./l. Caustic Soda 96°C for 30 minutes

Pigment Dyeing (Ionic Bond)

     

Pigments Cationic Agent Cotton

 

Cationisation agent of positive load adheres to the surface of fibre in a first operation named “pretreat” and then the dye of negative charge adheres to the surface of the cationic agent in

the second operation, the dyeing.

Pigment Cationic Agent Fiber

Fiber Cationic Pigment Effect of abrasion

Effect of AbrasionEffect of Abrasion

Ring dye process

Why fixing the dyes at the surface of the fiber?

All conventional methods of dyeing suggest to penetrate completely the fiber.In the ring dye process, we apply the dyes right onto the surface of the fiber to allow

subsequent wash down.

The mechanical action in the machine will contribute to give an old or worn out effect to the garment, which will appear to have been washed many times in a laundering

machine.

Scouring Process

30°C

1% Triwhite JET 5

60°C

5` 10` 10` 5` Dyeing

1%1% Soda ash Soda ash

Cationic Pretreatment Process

30°C

Tricowet TD-5

60°C

2` 5` 20` 15` 5` 10` 5` Dyeing

Tricellulase BPN

Acetic Acid Dosing Texafix BR

Pigment Dyeing Process

30°C

Texalev JL 60°C

2` 15` 10` 20` 20` 10` 5`

Pigment + Tri Binder AC-M-2240N

by dosing

Acetic Acid

option addition

Sample check

1. Rinse 20 ° C

2. Rinse 40 ° C

Pigments vs others types of dyeing

• Pigments Ionic bonds• Direct Forces of Van der Waalls• Reactive Covalent bonds• Sulphur Fixed by insolubilisation

Direct DyesThe direct dye being of negative charge just like cotton, makes them repulse. It is necessary in the case of the direct dyeings to use an ELECTROLYTE which will separate in positive and negative ions in the bath from dyeing.

•The positive ions will move towards fibre to fill the negative charge of cotton. •The negative ions will make competition with the dye of negative charge and will make it to go up on fibre by force of repulsion.

Salt will help the dye to get on fibre, the temperature will help with the swelling of fibre, and a neutral or

slightly alkaline pH to help with the solubilizing

groupings.

Classes of Direct DyesClass A: These dyes have a great capacity of migration even when electorlytes are involved. It can be unequal at the beginning, but will level out when a temperature of 205°F is reached

Class B: These dyes have less migration and use less électrolytes. The levelness of these dyes can be controlled by by salt addition. It is very important that the dye is also applied from the very start.

Classify C: These dyes have a very poor capacity of migration and they are very sensitive to the electrolytes. In certain cases these dyes exhaust quickly without addition of salt.

Note: When temperature decreases the affinity of the dye for fibre also decreases, but it increases its capacity of migration towards the other sites, thus improving levelness.

Procedure for Direct Dyes

30°C

96°C

50°C

Acide

Tricofix NZ

Trilube XTC

Soda

Dyes

Dose Salt

Precautions in production

The dissolution of the direct dye is done at the temperature of the cycle of dyeing, This means 96°C except for the black 22 were we add the dye to the

warm water already in agitation to avoid agglomeration of dye.

Dosing(proportioning) of the dye is done by the return water in the

addition tank .

Reactive DyesThe dye is not attracted towards fibre, we have to use an

electrolyte to push the dye towards fibre

The reactive grouping of the dye bonds with the alcohols group of the cellulose which is present as an atom and will form a very solid covalent

bond.

The reaction between fibre and the dye will release acide HCl, This is why it will be necessary to compensate with alkali to keep a pH of ±11. Deep

shade generate more HCL and consequently requires more alkali to obtain our pH.

Refer to table of Alkali for good fixation

Reactivity of the dyesTrichloro pyrimidineTrichloro pyrimidine Drimarene XZ

Monochloro trazineMonochloro trazine Cibacron E, Procion H/HE, Triactive HE

Vinyl Sulphone MonochlorotrazineVinyl Sulphone Monochlorotrazine Triactive DF

Vinyl SulphoneVinyl Sulphone Triactive & Remazol

Monofluoro triazine & Vinyl sulphoneMonofluoro triazine & Vinyl sulphone Cibacron C

Dichloro quinoxalineDichloro quinoxaline Levafix E

MonofluorotriazineMonofluorotriazine Cibacron F

Difluoro monochloro pyrimidineDifluoro monochloro pyrimidine Levafix E/A Drimarene K/R

Dichloro triazineDichloro triazine Procion MX

Low. Reactivity High

Precautions in production

• Add the dye in 30 minutes or more, • allowing good diffusion in fibre before adding alkali.

• Ensure to maintain a ph of ± 11 after the alkali addition to assure good fixation of the dyes.

The dissolution of the reactive dye is done at the temperature of the cycle of dyeing, Exemple: 60°C for

Triactive DF, or 80°C for Triactive HE. Add the dye powder to water with agitation, to not create agglomeration of dye

Dosing (proportional) of the dye and Alkali should be done with fresh water and not by the return water in the

addition tank

Soaping of the Reactive dyes

In this way the remaining electrolyte will be removed, thus reducing the affinity of the dye for fibre, thus helping the washing off. The dye not fixed and hydrolized will be removed in its turn and we will obtain better rubbing and washing fastness .

In reactive dyeing, usually the dye will be fixed on fibre, but there will be also hydrolized dyes on the surface of fibre.

Indeed certain bonds are done with fibre, but unfortunately some are also done with water.

For this reason it will be necessary after fixing, to rinse fabric very welland make a soaping with Triquest HON wich is a very good dispersing and

anti-redeposition agent.

Stripping of the Reactive dyes

4 gr./l. Caustic soda 50% heat to 80°C 2 gr./l. Tritex TD (Thioreadioxide) heat to 100°C Run for 30 minutes rimse and neutralize

1 gr./l. Soda Ash pH 10 - 11 20 gr./l. Sodium Hypochlorite (NaOCl) heat to 50°C run for 20 minutes RinseNeutralize with 2 gr./l. Sodium Métabisulphite 50°C for 15 minutes

Option #1

Option #2

Dyeing with Sulphur Dyes

These dyes are usually insoluble and require to be solubilized or reduced to be able to penetrate fibre.

They will be finally rendered insoluble again to remain permanently.

Example formulation of the bath reductor for 18 % of dyeing

1.0gr./l. Tridefoam AGD 1.0gr./l. Triquest XRD 0.5gr./l. Technowet SW-1 30.0 gr./l. Salt 12.0 gr./l. Dextrose 11.0 gr./l. Caustic Soda 50% 18% owg Tricosulphur Black RC liq.

Temperature 96Temperature 96° C for 30 minutes C for 30 minutes

(For Deep Black Shades)(For Deep Black Shades)

Procedure for Sulphur Dyes

4040°C

AGDAGD

XRDXRD

SW-1SW-1

Salt, Dextrose, CausticSalt, Dextrose, Caustic

8585°C

Tricosulphur Black RC liq.Tricosulphur Black RC liq.

9696°C

8080°C

OverflowOverflow rinse.rinse.

SodaSoda

Trioxy ALTrioxy AL

5050°C33°C min.

1°C min.

10’ 20’ 20’ 10’ 30’ 20’ 10’ 20’ 20’ 10’ 30’ 20’ 

Procedure for Sulphur DyesProcedure for Sulphur Dyes

Oxidation of suffur dyesOxydation of this dye is very important to obtain good fastness.

Alkaline Oxidation

1 gr./l. Soda ash 2% Trioxy AL

50 °C for 20 minutes

Trioxy AL remains the best, since we stay in alkalinemedium. The danger in the dyeing with sulphurs would be to leave the

material in acid medium at the end of the cycle, which could lead to tenderizing of fibre by sulphuric acid formation during the

warehousing time.

Thank You!