Application of disperse dyes on 100% Polyester and its blends with cotton and viscose

General process sequence for PC blended fabric is:

 

 

 

Recipe:

• Disperse dyestuff = x %
  
• Nugen LFT = 0.5 %
  
• Acetic Acid = 1.5 %
  
• Carrier = 0.5%
  

If the recipe contains a Navy Blue dyestuff, then pH should 4.5 to 5.0 during dyeing, otherwise navy will tend to exhaust partially and hence unlevel dyeing. (If Formic Acid is available replace Acetic acid 1.5% with 1.0% of it, it is the most stable acid at high temperatures rather than Acetic).

Nugen DFT concentration need not be increase more than 0.5%. It is in fact, leveling and retarding agent; that will impair the depth and fastness.


Dyeing Procedure:

1. Pretreatment:
   
   1. Acetic Acid = 1.5 g/l
      
   2. Nugen DFT = 0.3 g/l
      1. Treat at 50⁰C for 10 minutes
         
2. Dyeing:
   
   1. Add dissolved disperse dye solution at 50⁰C = addition time = 10 minutes
      
   2. Raise the temperature to 115⁰C @ 2⁰C/minute; at 115⁰C hold for 10 minutes
      
   3. Raise the temperature to 135⁰C @0.5⁰C/minute; at 135⁰C hold for 30 to 45 minutes
      
   4. Cool to 80⁰C and drain
      
3. Reduction Clearing:
   
   (Alkaline)
   
   
   1. Caustic Soda = 2 gpl
      
   2. Hydros = 2 gpl
      
   3. Dispersol VLH = 1 gpl
      
      1. Treat at 50⁰C for 20 minutes
         
      2. Cold wash – Acetic acid wash with acetic acid – 1 gpl 10 minutes.
         
   (Acidic)
   
   
   1. Cyclonon ECO = 2gpl
      
   2. Acetic Acid = 2 gpl
      
      1. 
         Treat at 80⁰C for 20 minutes
         
      2. Cold Wash 10 minutes; unload.
         

Please find below a general process sequence for Polyester Cotton blend:

Process Flow for PC and PV blends:

 

 

 











Some reasons for un-level dyeing:

• Highly pH sensitive disperse dyes – almost all navy's and blacks
  
• Too much loading
  
• Liquor Circulation problems
  
• Improper heat setting/no heat setting
  
• Too less quantity of Leveling /dispersing agent
  
• Inadequate quantity of Acetic/Formic acid (please check acid concentration- acetic acid is being manufactured from different sources.) pH plays a major role in disperse dyeing levelness – take care.
  

Other Defects noticed in polyester dyeing:



Moire Effect on PC or PV – woven/knitted:

A watered, clouded, or frosted wavy appearance produced upon either woven or knitted textile fabrics is said to be moiré effect.

The moiré effect is caused mainly due to the differential shrinkage of polyester and cotton or viscose at high temperature and high pressure dyeing. This problem can be avoided by taking proper precautions before and after dyeing.

1. A perfect head setting on pins at a temperature of 200 to 210⁰C for 30 to 45 seconds with an over feed of 6 to 8% may be done.
   
2. In case of PV blends, caustizisation with 10 to 12⁰TW of caustic soda at room temperature may minimize moiré effect.
   
3. Moire effect after dyeing may be corrected either by caustizisation or treating the fabric with 3 to 5 gpl of carrier at 130⁰C for 30 minutes in a jet or soft-flow machine.
   
4. This can also be corrected by subjecting the fabric to high temperature at 200⁰C with an over feed of 6 to 7% and redye in HT + HP machine using 10% of disperse dye recipe for 30 minutes.
   

Poor Sublimation Fastness:

• Some of the disperse dyes tend to crystallize while cooling down the exhausted bath from 135⁰C to 80⁰C. 100⁰C is the most critical temperature at which some of the red disperse dyes ( C.I.No. 53, 60, 131, 132 and 159) give problem of crystallization when they are dyed at higher depths and especially if the dyeing is carried out in hard water. The hardness of water should be nil for disperse dyeing.
  
• Some of the disperse dyes are very sensitive to metal ions and shade changes considerably bluer to duller side. Spinning assistants, spinning oils, alkaline residues and other factors cause crystallization of disperse dyes to produce dye specks. This problem may be solved by proper pretreatment.
  
• The chromophore of the azo based disperse dyes is reduced and become soluble when an alkaline reducing agent (caustic & hydros) at 60C thus promoting poor sublimation and rubbing fastness
  
  Na2SO4 + 2 H2O -------à 2H + 2NaHSO3
  
  (alkaline condition)
  
  -N=N- + 4H --------à -NH2-NH2- (soluble disperse dye)
  
  Azo dye
  
• Use of non-ionic auxiliaries in the dye bath may also tend to aggregate some of the disperse dyes causing poor sublimation and rubbing fastness.
  

These problems can be overcome by using the following recipe:

• Disperse dye = x %
• Acetic acid = 1.0 gpl
• Sodium Acetate = 0.5 gpl
• Anionic dispersing agent = 1.0 gpl
  

Or

• Disperse dye = x %
  
• Formic acid = 0.35 to 0.5 gpl
  
• Ammonium Sulphate = 1.0 gpl
  
• Anionic dispersing agent = 1.0 gpl
  

Dye Specks:
Dyeing auxiliaries like carrier, leveling agents (non-ionic) are liable to nullify the effect and impair the solubilizing effect of dispersing agents thus promoting aggregation and agglomeration of disperse dyes causing specks.
Also use of non-ionic silicones during final finishing tend to aggregate disperse dye and reactive dyes; reduces the sublimation /rubbing fastness of the dyed fabric.
Non-ionic products in the form of wetting, leveling and finishing agents may be curtailed to avoid these problems.


Pilling:
Factors responsible for pilling:

1. Fiber Characteristics such as morphological, chemical and fine structure of the fiber, fiber length, fineness, strength etc.
   
2. Yarn Characteristics – viz., blend, count, twist, hairiness
   
3. Fabric Characteristics – such as weave, ends and picks etc.
   
4. Frictional and abrasive force – such as linear or rotational rubbing forces encountered during wear or processing.
   

Remedies:

• Surface treatment: The protruding fibres from the yarn or fabric can be removed mechanically/chemically or by burning out or cropping, surface carbonizing, singeing, heat setting etc reduces pilling.
  
• Steaming & cropping: the loose projecting fibres are removed mechanically by sharp blades from the surface of the fabric to a certain extent and that helps in reducing pilling.
  
• Surface carbonizing: In this technique, the protruding fibres are burnt or dissolved with suitable chemicals – the nature and the amount of chemicals used depends on the constituents of the blended fabrics. The fabric is thus not only free from pilling but also gives surface feel.
  

Disperse Dyes in Printing

 Methods of printing with Disperse Dyes – a practical over view

Nuchem Dyestuffs P Ltd., (NDPL), suggests the following 3 methods for printing with disperse dyes. These methods can be used in flat-bed and rotary screen printing machines.

Method-1:

PRINTING - DRYING - BAKING - REDUCTION CLEARING - WASHING OFF

1.       PRINTING

Recipe	Full Thickening	Half Thickening
Disperse Dyes	X - parts	X – parts
Alginate thickener (10% conc)	600 - parts	450 – parts
Emulsion thickener	Nil	150 – parts
Anti-Reducing Agent (mild Oxidizing agent)	5 – parts	5 - parts
Citric Acid	2 – parts	2 – parts
Wetting Agent	20 – parts	20 –parts
Add water to make	1000 parts	1000 parts

2.  DRYING – on stenter at 100 – 105°C

3.  BAKING – on Curing machine

-    Temperature                210 ⁰C

-    Time                              60           second

4.  REDUCTION CLEARING (RC)

-          NaOH flake                                  2              gram / litre

-          Sodium hydrosulphite                 2              gram / litre

-          Dispersing agent                         2              gram / litre

-          Temperature                               60 ⁰C

-          Time                                            10 minutes

5.  WASHING OFF

Method-2:

PRINTING - DRYING - HT STEAM -  REDUCTION CLEARING - WASHING OFF

1.           PRINTING

Recipe	Full Thickening	Half Thickening
Disperse Dyes	X - parts	X – parts
Alginate thickener (10% conc)	600 - parts	450 – parts
Emulsion thickener	Nil	150 – parts
Anti-Reducing Agent (mild Oxidizing agent)	5 – parts	5 - parts
Citric Acid	2 – parts	2 – parts
Wetting Agent	20 – parts	20 –parts
Add water to make	1000 parts	1000 parts

2.           DRYING

3.       HIGH TEMPERATURE (HT) STEAM

-          Temperature                170 ⁰C

-          Time                              8 minutes

4.       REDUCTION CLEARING (RC)

-          NaOH flake                                  2              gram / litre

-          Sodium hydrosulphite                 2              gram / litre

-          Dispersing agent                          2              gram / litre

-          Temperature                                 60 ⁰C

-          Time                                              10   minutes

5.       WASHING OFF

Method – 3:

PRINTING   - DRYING   - HP STEAM   -  REDUCTION CLEARING   - WASHING OFF

1.           PRINTING

Recipe	Full Thickening	Half Thickening
Disperse Dyes	X - parts	X – parts
Alginate thickener (10% conc)	500 - parts	250 – parts
Emulsion thickener	Nil	450 – parts
Anti-Reducing Agent (mild Oxidizing agent)	2.5 – parts	2.5- parts
Wetting Agent	10 – parts	Nil
Add water to make	1000 parts	1000 parts

2.       DRYING

3.       HIGH PRESSURE (HP) STEAM

-          Temperature                130 ⁰C

-          Time                              20 minutes

4.       REDUCTION CLEARING (RC)

-          NaOH flake                                  2              gram / litre

-          Sodium hydrosulphite                 2              gram / litre

-          Dispersing agent                         2              gram / litre

-          Temperature                                60 ⁰C

-          Time                                             10   minutes

5.       WASHING OFF

Notes:

1.       Disperse Dyes                 : Nusperse Dyes (Nuchem Disperse Dyes)

2.       Alginate thickener         : Manutex F  , etc

3.       Emulsion thickener        : mixture from water , white spirit and emulsifier

4.       Anti reduction                : Matexil PAL , Ludigol , sodium chlorate , etc

5.       Wetting agent for print paste           : Matexil WA-KBN , etc

6.       Dispersing agent           : Matexil DN-VL , Solopol ZB , etc

Nuchem Dyestuffs P Ltd.,–Concentrated Direct Blacks

 

NDPL has launched its concentrated series of Direct Black-22 and has been exporting large volumes to Bangladesh, Indonesia, Thailand and Jordan.

The various concentrations available with NDPL are:

Direct Black VSF – 1600%

Direct Black VSF – 800%

Direct Black VSF – 600%

All the above highly concentrated versions widely used in garment sectors of the above mentioned countries.

Apart from Blacks, Browns and Bottle Greens of direct dyestuffs have also been exported by NDPL.

People interested to have business contacts from countries other than the above may visit our website http://www.nuchemdyestuffs.com or write to patel.nuchem@gmail.com

Dyestuff Selection - manufacturers' suggestion - an important phase in processing

Selecting the proper trichromatic combination of 3 dyes that have almost similar substantivity, exhaustion and fixation properties is very important for getting the best reproducible shade matching.

Nuchem Dyestuffs P Ltd., is making the following suggestions for its customers.


General guidelines:

LIGHT SHADES	MEDIUM SHADES	DARK SHADES
For Good Light fastness and levelness: Cotfix Yellow CA Cotfix Red CA Cotfix Blue CA Cotfix Amber CA Cotfix Yellow FN2R Cotfix Red FN2BL Cotfix Blue FNR Cotfix Blue FNG For all round optimum fastness: Cotfix Yellow RR Cotfix Red RR Cotfix Blue RR Cotfix Yellow 5GL Cotfix Yellow F3R Cotfix Red F3B Cotfix Blue BB Cotfix Blue BRN	For Good Light fastness and levelness: Cotfix Yellow FN2R Cotfix Red FN2BL Cotfix Blue FNR Cotfix Blue FNG For all round optimum fastness: Cotfix Yellow RGB Cotfix Red RGB Cotfix Blue RGB Cotfix Navy RGB Cotfix Caramine RGB Cotfix Yellow NL-2R Cotfix Red NL-5B Cotfix Blue NL-BR Cotfix Navy NL-R	Dark Shades: Cotfix Yellow RGB Cotfix Red RGB Cotfix Blue RGB Cotfix Navy RGB Cotfix Caramine RGB Cotfix Ultra Yellow RGB Cotfix Ultra Red RGB Cotfix Yellow D Cotfix Red D Cotfix Navy DB Cotfix Orange D Cotfix Deep Red DB Cotfix Dark Blue DB

This guideline is only a general thumb rule and one should not come to a conclusion that this is the ultimate criteria. The dyer, based on his final requirement or end use of the dyed material, has to select proper group of dyestuff.

CA, FN and NL series would meet the wide range of fastness requirements of the industry.

RGB and Ultra RGB series are most suitable for medium and dark shades, where one would expect no metamerism.

W series are exceptionally suitable for wide range of dark shades, where economy is of prime importance. With series generally one can dye uniforms like dark browns, Olives and Dull blues.

D series posses exceptionally all sound fastness parameters and are economical too for dyeing dark and very dark shades.

HF series produce exceptionally bright shades and possess very high tinctorial values, most suitable for dyeing and printing, exhaust and CPB applications.

This classification is further elaborated as below:

1.     Lemon Yellow

2.     Yellow, Golden Yellow

3.     Orange, Scarlet

4.     Red

5.     Wine, Maroon

6.     Violet

7.     Blue, Royal

8.     Turquoise, Bright Green

9.     Navy Blue, Black

10.  Beige, Light Blue, Grey

11.  Brown

12.  Dark Green, Olive

 

Lemon Yellow

Cotfix Yellow 5GL

Cotfix Yellow ME4GL

Cotfix Yellow F4G

Yellow, Golden Yellow

Cotfix Golden Yellow F3R

Cotfix Red F3B

Cotfix Blue BB

Cotfix Yellow GR

Cotfix Orange 2R

Cotfix Orange 3R

Cotfix Orange ME2RL 

Orange, Scarlet

Cotfix Orange 3R

Cotfix Orange ME2RL

Cotfix  Oange 2R

Cotfix Yellow F4GL

Cotfix Yellow GR

Cotfix G.Yellow RNL 150%

Cotfix Red F3B

Cotfix Navy Blue BFN

 Red

Cotfix Yellow GR

Cotfix G.Yellow RNL

Cotfix Orange 3R

Cotfix Orange 2R

Cotfix Orange D

Cotfix Deep Red DB

Cotfix Red D

Cotfix Scarlet HF-3G

Cotfix Orange HF-2GL

Cotfix Blue BB

Wine, Maroon

Cotfix Yellow GR

Cotfix Yellow RNL-150%

Cotfix Deep Red DB

Cotfix Caramine RGB

Cotfix Ultra Red RGB

Cotfix Navy Blue RGB

Cotfix Navy Blue BFN

Cotfix Blue R SPL.

 Violet

Cotfix Golden Yellow F3R

Cotfix Orange ME2RL

Cotfix Red ME6BL

Cotfix Red ME4BL

Cotfix Violet 5R

Cotfix Navy Blue R SPL

Cotfix Navy Blue BFN

Cotfix Blue BRN

Blue, Royal

Cotfix Blue BRN

Cotfix Navy Blue BFN

Cotfix Golden Yellow R 150

Cotfix T/Q Blue H2GP, G

Cotfix Blue R spl

Cotfix Blue BB

Turquoise, Bright Green

Cotfix Yellow F4G

Cotfix Golden Yellow F3R

Cotfix Yellow ME4GL

Cotfix Blue R SPL

Cotfix T/Q Blue H2GP

Cotfix Blue BB

Navy, Black

Cotfix Golden Yellow R 150

Cotfix Red ME6BL

Cotfix Red RGB

Cotfix Red ME4BL

Cotfix Navy Blue R spl

Cotfix Navy Blue BFN

Cotfix Black ECO

Cotfix Black WNN

Cotfix Supra Black G

Cotfix Black B 133%

Beige, Light Blue, Grey

Cotfix Blue BRN

Cotfix Yellow RR

Cotfix Red RR

Cotfix Blue RR

Cotfix Yellow CA

Cotfix Red CA

Cotfix Blue CA

Cotfix Red HF-G

Brown

Cotfix Golden Yellow WR

Cotfix Red WB

Cotfix Navy Blue WB

Cotfix Orange W3R

Cotfix Dark Blue WR

Cotfix Yellow RGB

Cotfix Red RGB

Cotfix Blue RGB

Cotfix Navy RGB

Cotfix Caramine RGB

Cotfix Ultra Yellow RGB

Cotfix Ultra Red RGB

Cotfix Yellow D

Cotfix Red D

Cotfix Navy DB

Cotfix Orange D

Cotfix Deep Red DB

Cotfix Dark Blue DB

 Dark Green, Olive

Cotfix yellow RGB

Cotfix Red RGB

Cotfix Blue RGB

Cotfix Navy RGB

Cotfix Yellow D 

Cotfix Red D

Cotfix Navy DB

Cotfix Orange D

Cotfix Deep Red DB

Cotfix Dark Blue DB