Helo, reders welcome to my website”textilesgreen.in” today I m going to explain about reactive dye, reactive dyeing process, properties, classification and types.

reactive dye, dyeing process

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reactive dye is more sutable and profitable for cellulose materials. and it’s gives posstive effect on cellulose materials.
this is the reason, mostly in textile industry reactive dyeing is used for cellulose materials.

reactive dye have capability to makes covalent linkage with the fibre. and work as a integral part of fibre.


this covalent is formed between 
the dye molecules and the OH hydroxyl group of cellulosic
fibers on between the dye molecules and the terminal -NH2
group of polyamide.

what is reactive dye

A dye, which is capable of reacting chemically with
a substrate to form a covalent dye substrate linkage, is
know as reactive dye.
reactive dye can be dyed such as,
Cotton, wool divers, silk.

reactive dyes types

Here, I m going to explain about reactive dyes types.

1. Hot brand reactive dye

2. Cold brand reactive dye

3. Lower temperature reactive dyes
4. HE brand reactive dye

5. ME brand reactive dye

reactive dyes properties

1. Reactive dyes are soluble in water.
2. Reactive dyes are  comparatively cheap and best.
3. Easy dyeing methods and it require less time for dyeing
4. It require low temperature for dyeing
5. Reactive dye having good perspiration fastness with rating 4-5.
6. Reactive dyes have very good wash fastness but has moderate
rubbing fastness.
7. Reactive dyes have very good light fastness with rating 6.
8. reactive dyes are found in power, liquid and print past form.
9. Reactive dyes are anionic dyes, which are used for dyeing
cellulose, protein, and polyamide fibers
10. Dyes have stable electron arrangement and can protect the degrading effect of ultra-violet ray.
11. Easy methods
12. dyeing with low temperature.
13. Reactive dyes are also found in liquid and print paste form.
14. Cheap process
15. Make a covalent bond with the fibre and work as a integral part of the fibres.
16. reactive dyeing is gives posstive effect on cellulose materials.
17. reactive dyes have more solubility in water.
18. light fastness is good
19. Washing fastness is also good.
20. rubbing fastness is moderate.

Some important chemicals is used in reactive dyeing

• Salt
• soda ash
• urea
• sodium alginate

Salt –

(a) Increases absorption.

(b) Decrease hydrolysis rate of dyes.

(c) help in extra energy for pantration.

(d) NaCl is widely used for reactive dyeing.

(e) improve affinity energy of dye.

PH –

(a) high PH is required in reactive dyeing because without high PH,
Dye will not fixed properly or parmanently to the materials.

Sodium carbonate is used to maintain PH in case of reactive dyeing.

Time –

The role of time is very important in case of Dyeing because accurate or proper fixation is depand upon time. If increase of the time then fixation of dye will increase.

Its give good, wash fastness, rubbing fastness, light fastness, perspiration fastness.

Temp –

In case of cellulose materials, if used high temperature caused the cotton material to have no or poor ability to be dyed. It effects on cellulose materials. Cellulose materials is not gives good results.
And increase the ability to reaction mechanism during dyeing.

Two phases Occur during dyeing

1. Exhaustion phase

( Proper dye absorption)

2. Fixation phases

(Proper dye reactions)

Shade is devlop with the help of salt and soda ash during dyeing

The role of salt and soda ash in reactive dyeing is very important beacause its gives proper shade
On dyed materials.
There are three types of shade is devlop with the help of salt and soda ash.

• Light shade

• medium shade

• deep shade

But it is depand upon quantity of salt and soda ash during dyeing.

reactive dye having capacity to dyed

• cotton ( yarn, knit, woven)

• natural fibre ( cellulose materials)

reactive dyes classification

1. reactivity system in dyeing

 
a)In case of reactive dyeing, there are two phases are work. Lower reactive dyes and medium reactive dyes. in case of reactive dyeing,

PH is maintained 11-12 by using Na2CO3 in dye bath.

b)in case of higher reactive dyes,

PH is maintained 10-11

by using Na2CO3 in dye bath.

2. temperature system of dyeing

a) cold brand

In case of cold brand reactive dye, Dyes contain reactive group of high reactivity. so dyeing can be done in lower temperature (320-360).

 this type of dyes contain reactive group of moderate reactivity so dye is done  in higher temperature then
that of cold brand dyes, in between 600-710C.

b) Hot brand

This type of dye contains reactive group of  least reactivity. so high temperature is required for dyeing 
i.e. 720-930 C
for example pricion H cibacron are hot brand dyes.








reactive dyes machanism

 

 

dyeing of cotton fabric with reactive dyes: - textilegreen

function of NaCl

Here, if used NaCl as the electrolyte. this electrolyte is properly neutralize absorption. so when the textile material is
introduces to dye liquor the dye is exhausted on to the fiber.

fixation system of reactive dye

In case of reactive dyeing, The reactive group of dye is directly reacted with terminal OH or -NH2 group of fibre. and its gives strong covelant bond with the fibre.
Alkali is also very important role in reactive dyeing. Because alkali create proper PH in dye bath.
In case of reactive dyeing, maintain PH with the help of alkali. If alkali is add in dye bath its creat proper PH in dye bath.

In other words, it is also called dye fixing agent.


washing system of reactive dye

If dyeing is completed then washing is  must be required for textile materials because if unfixed dyes persent on the surface of the materials it is easily removed with the help of washing. and it’s also help in wash-fastness. It is done with the help of hot washing and then again cold wash.
and after this soaping is also required for textile materials.
 

reactive dyeing methods system


(a) Discontinous methods

• Hot brand

• Cold brand

(b) Continous methods

• Pad system methods

• Pad thermo fixation methods

(c) Semi – continous methods

• pad roller methods

• pad jigger dyeing methods

recipe of cold brand reactive dyeing methods

• Dye – 1- 3%

• salt –   60 gm/c

• soda ash – 15 gm/c

• H2O –         10 times

• Temp –   40°C

• Time –     1 hours

Procedure


                       start

                           |
    take required water in dye bath

|
      Add soda ash in dye bath

|

After 10 mint add salt

|

add materials in dye bath

|

Continue Dyeing at 40°C for                            1 hours
|

Wash

|

Dry

|

End



Stripping system 

Stripping ia also necessary when uneven dyeing occurs.
In case of reactive dyeing
partial stripping is obtained by treating the dye fabric
with dilute acetic acid or formic acid. here, in case of stripping of reactive dyeing. temperature
is raised to 70-100C and treatment is continued until
shade is product of hydrolysis.
amount of acid used is
as below:
for example:


Glacial acetic acid     – 5-10 parts
water                           –  1000 parts

Conclusion:

Image result for dyeing of cotton with reactive dye photo
 
In case of reactive dyeing, we came to know the
reactive dye are of the least reactivity because
they take more temperature and more time for dyeing.

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1 Comment

Ujjwal kumar · November 17, 2019 at 3:49 pm

All articles aare very good.. Very helpful for me.. Thanku Rahul Shukla jii🙏🙏

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