This document provides a project report on the reaction mechanism of reactive dyes in Bengal Hurricane Group on cellulose fiber. It discusses the raw materials used, including fabrics, dyes, and chemicals. It explains the importance of studying reactive dye usage in major Bangladeshi textile industries. The methods of dyeing and printing cotton with reactive dyes and the technical deficiencies, causes, and remedies are examined.
DEFINITION: Pigment is a substrate in a particulate form which is insoluble in water but which can be dispersed in this medium to modify its color and light scattering properties. They are organic or inorganic coloring materials. They have no affinity to textile materials. They are fixed on the textile material with the help of binding agent in form a thin invisible coating.
DEFINITION: Pigment is a substrate in a particulate form which is insoluble in water but which can be dispersed in this medium to modify its color and light scattering properties. They are organic or inorganic coloring materials. They have no affinity to textile materials. They are fixed on the textile material with the help of binding agent in form a thin invisible coating.
Special Instruction:
Fabric shrinkage must keep within ±5%
Color fastness should be 4-5 range
Pilling range 3 to 5
pH range 5.5 to 7
Fabric weight will be allowed ±02%
Fabric quality should be s per approved swatches & Lab-Dips.
Batch to batch color matching should be 4-5
Batch to batch “Shade Band Swatch” must be submitted for approval.
Lab dip is a process by which buyers supplied swatch is matched with the varying dyes percentage in the laboratory with or without help of “DATA COLOR”
Lab dip plays an important role in shade matching & and detaching the characteristics of the dyes and chemicals are to be used in the large scale of production. So this is an important task before bulk production.
Softener is an finishing agent that when applied to textile material improves its handle giving pleasing touch. As a general rule, the softening agents applied are lubricating agents, which facilitate the fiber sliding within the fabric structure, thus granting easier deformation and creasing of the fabric.
Classification of dyes; Dyeing of cotton, wool, silk, polyester, nylon and acrylic with appropriate dye classes; Dyeing of polyester/cotton and polyester/wool blends; Dyeing machines; Dyeing of cotton knitted fabrics and machines used; Dye fibre interaction; Introduction to thermodynamics and kinetics of dyeing; Methods for determination of wash, light and rubbing fastness.
LYCRA,SPANDEX AND OTHER ELASTANE DYEING WITH DIFFERENT COLOR COMBINATIONS AND DYES AND ITS PROCESS STUDY ACCORDING TO TEMPERATURE AND PRESSURE SUITABILITY ACCORDANCE TO DYEING PARAMETERS
Special Instruction:
Fabric shrinkage must keep within ±5%
Color fastness should be 4-5 range
Pilling range 3 to 5
pH range 5.5 to 7
Fabric weight will be allowed ±02%
Fabric quality should be s per approved swatches & Lab-Dips.
Batch to batch color matching should be 4-5
Batch to batch “Shade Band Swatch” must be submitted for approval.
Lab dip is a process by which buyers supplied swatch is matched with the varying dyes percentage in the laboratory with or without help of “DATA COLOR”
Lab dip plays an important role in shade matching & and detaching the characteristics of the dyes and chemicals are to be used in the large scale of production. So this is an important task before bulk production.
Softener is an finishing agent that when applied to textile material improves its handle giving pleasing touch. As a general rule, the softening agents applied are lubricating agents, which facilitate the fiber sliding within the fabric structure, thus granting easier deformation and creasing of the fabric.
Classification of dyes; Dyeing of cotton, wool, silk, polyester, nylon and acrylic with appropriate dye classes; Dyeing of polyester/cotton and polyester/wool blends; Dyeing machines; Dyeing of cotton knitted fabrics and machines used; Dye fibre interaction; Introduction to thermodynamics and kinetics of dyeing; Methods for determination of wash, light and rubbing fastness.
LYCRA,SPANDEX AND OTHER ELASTANE DYEING WITH DIFFERENT COLOR COMBINATIONS AND DYES AND ITS PROCESS STUDY ACCORDING TO TEMPERATURE AND PRESSURE SUITABILITY ACCORDANCE TO DYEING PARAMETERS
Difference between reactive dye and disperse dye on fabricAzmir Latif Beg
We are introducing about reactive dye and disperse dye on fabric. At present reactive dye and disperse dyes is not a single word globally now it achieved vast sector in dyeing sector. I just try to make a different reactive dye and disperse dye on fabric application based.
It has great effect of hot brand reactive dye on cotton fabric with exhaustion method. Migration method is more acceptable for proper color fixation in a dyeing process. Another way when we followed ISO method has create a lot of problem such as wash fastness variation rubbing fastness variation, uneven dyeing etc. If we want to get perfect dyeing than we must maintain migration method.
Analyzing different fabric properties after garments dyeingS.M. Zahidul Islam
The garment dyeing process has a lot influence on the properties of different woven fabrics. Commercially garment dyeing is relatively newer field in Textile processing. Here we have used different parameters to get result. It just an example of an experiment which we were trying to find out the facility of the different fabrics after garments dyeing.
Special Note: Everyone is requested to avoid these slide to use exactly same, It can be used just an example.We will be trying to improve the DRAWBACK of this experiment.
Color fastness properties of different reactive dyesAzmir Latif Beg
In knitwear industry, dyeing of cotton knitted fabrics is mostly done with reactive dyes, because of their good fastness properties and versatility of applications. The ease of application, wide shade range, high brilliancy and excellent wet fastness properties make the reactive dyes preferred choice for the dyeing of cellulosic fabrics. The most important characteristic of reactive dyes is the formation of covalent bonds with the substrate to be colored, i.e. the dye forms a chemical bond with cellulose. Fiber reactive dyes are the most permanent of all dye types. Unlike other dyes, it actually forms a covalent bond with the cellulose or protein molecule. Once the bond is formed, what you have is one molecule, as the dye molecule has become an actual part of the cellulose fiber molecule.
Sustainable dyeing process to cope with Industry 4.0Emran Ali
Value addition for textiles is an important process and it is required for all products including yarn, fabric, garment, fashion apparel, floor covering, and the majority of technical textile. For each textile processing, the processor used enormous amounts of chemicals and water in order to attain the desired result. After processing the residual processed chemicals and waters are treated with effluent treatment and discharged into the mainstream. The amount of residual unfixed dyes, metal compounds, formaldehyde-based dye-fixing agents, hydrocarbon-based softeners, and all types of dye-bath auxiliaries, as well as their degradation nature against the environment, are the deciding factors for its sustainability. There are many factors influencing the overall efficiency or value addition of a textile product, which play an important role in its sustainability.
Study on cost effectiveness of silk dyeing with acid dyes and basic dyesMd. Ariful Islam
This project report aims to make a comparative analysis of silk dyeing with acid dye & basic dye.This study
emphasizes on the total costing for dyeing, different types of fastness properties (wash, rubbing, perspiration
and light), dye uptake of the dyed samples.It is found that acid dyes shows better dye uptake % for red color
while basic dyes showed better dye uptake for blue and yellow color. Color fastness on silk for acid dyes
is better than basic dyes and also dyeing with basic dyes is comparatively economical than acid dyes.Our
project work suggests that silk dyeing with acid dyes is more suitable from the point of view of fastness
properties, dye uptake than basic dyes. On the other hand, basic dyes are more suitable from the point of
view of cost. In future we can apply basic dye along with acid dye through vigorous research and process
development.
Effect of Alternative Scouring Agents on Dyeing Properties of Cotton/Polyeste...IOSR Journals
This research comprises of six alternative agents ((NH4)2C2O4, liquid NH3, CH3COOH, NH4OH, (COOH) 2, CH3CH2OH) at various concentrations of 1-5% used as scouring agents with NaOH as control on cotton/polyester blend fabric. The samples were bleached, mercerized and dyed. The suitability and reliability of the agents were evaluated for dyeing properties of the treated fabric. Water imbibing properties of the treated fabric, was investigated. The experimental results showed that the percentage exhaustion of indigo dye on the treated fabric were wonderful with values far above average (86.8-62.6%) except for 1% (NH4)2C2O4 that recorded slightly below average (49.7%). 2% liquid NH3 ranked the highest. The wash fastness is another interesting results where only 1-5% liquid NH3, 2% and 4% (NH4)2C2O4 that gave a grey scale rating for wash fastness of 4 (very good). The other alternative agents strongly competed at various concentrations with the control which revealed a rating of 5 (excellent wash fastness). 4% (NH4)2C2O4 scoured fabrics recorded the highest water of imbibitions (2.9 g). This implies that the alternative agents are suitable and reliable as impurity-removing (scouring) agents. The alternative agents improved the dyeing and water imbibing properties of the treated fabric far better than the control. Therefore could be employed in the textile industry.
Fixing agent is one of the important textile auxiliaries in dyeing and printing industry, which can improve the color fastness of dye in fabric. On the fabric, it can form insoluble colored material with dye, thus to improve the color of washing, perspiration fastness, and sometimes can improve its sun fastness.
In recent years, with the development of science and technology, dyeing and finishing technology has also been significantly improved. Due to the expansion of international textile trade and the improvement of people's living standards and environmental awareness, it's more required of textiles comfort, clean and safety. Since the 1970s, Germany first launched the "Blue Angel" plan, the world's developed countries (Japan, the United States, etc.) have passed and implemented the related laws, regulations, and rules for the various indicators of textiles. Green textiles require that in the printing and dyeing process prohibit the use of carcinogenic, teratogenic, poor biodegradability of poor and some aromatic amine intermediates banned in the regulations. At the same time, the use of additives not contain heavy metal ions and not producing free formaldehyde is also required, which means the use of "green auxiliaries”.
Classification
The commonly used color fixing agent for dyeing and printing in textile has cationic fixing agent, such as Cetylpyridinium Chloride, Cetylpyridinium Bromide; fixing agent Y; polyamine contraction (silk fixing agent la); crosslinking fixing agent; non formaldehyde dye fixing agent, and phenolic sulfonate formaldehyde condensate used for nylon (polyamide) fabrics instead of tannin as fixing agents.
Preparation
Take the fixing agent y as an example: After adding the quantitative double cyanide amine to the atmospheric pressure reaction kettle to dissolve, in order to quantify the formaldehyde solution in the constant agitation slowly drops into the reactor, finally uses the ammonium chloride neutralization, produces the certain solid quantity transparent viscous liquid to be the finished product. This method produces the formaldehyde fixing agent, the solid color effect is good but there is free formaldehyde pollution problem, which is now banned in many products.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
How to Split Bills in the Odoo 17 POS ModuleCeline George
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The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
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This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
3. CONTENTS
• Introduction
• Raw Materials
• Importance of The Survey
• Reason of using Reactive dyes in major textile
industry in Bangladesh
• Methods of Dyeing & Printing Cotton Goods
with Reactive Dyes
• Technical Deficiency of Reactive Dyes, Causes
and Remedies of Technical Deficiency
• Conclusion
4. Chapter 1
Acknowledgement
Project Work is an academic function of the Pabna Textile Engineering College. Our teacher Md. Abdul Mannan,
Principal, Pabna Textile Engineering College, gave us an opportunity to choose preferable mills for Project Work. I
chose Bengal Hurricane Dyeing & printing (pvt.) Ltd. joyfully with the supervision of Mithun Biswas, Asst.
Manager(production).
During the Project with Bengal Hurricane Dyeing & printing (pvt.) Ltd. I worked in all the departments related with
Dyes and Chemicals. Beside these, I learned about Dye Quality Control and Storage System,printing, Garments,
Store & Inventory , finishing & specially dyeing.
Our deepest appreciation goes to Mithun Biswas, Asst. Manager(production)Dyeing, Bengal Hurricane Dyeing &
printing (pvt.) Ltd. to give us the opportunity to have project work at BENGAL HURRICAN GROUP.
I would like to thank Engr. Md. Iqbal Mahamud (Head of the Factory), GM, Dyeing, Bengal Hurricane Dyeing & printing
(pvt.) Ltd. for helping to know about the all aspects of BENGAL HURRICAN GROUP.
I would also like to thank Tareq Ahmed(Deputy Manager),Md.Anwarul
Islam(Deputy Manager), Md. Arif Rabbani Talukdar(Deputy Manager),Dyeing, Bengal Hurricane Dyeing & printing (pvt.)
Ltd. for helping to know about the all aspects of BENGAL HURRICAN GROUP.
Our gratitude also goes to all the employees of BENGAL HURRICAN GROUP for their sincere co-operation, support and
valuable advice which they have provided us during the two months of training.
Lastly I express my gratitude to our supervising teacher, the name that should be mentioned first, Shib Shankar
Chakraborty, Head of the Dept. Wet Processing Technology for his valuable direction & supervision.
However, I have prepared my Industrial Attachment overcoming all the difficulties & also the shortage of time. Here I
would like to present the report.
•
7. Chapter:3
Project Abstract
•
The use of reactive for Dyed products has dramatically increased over the last 50 years. Reactive dyes
are now used to produce multiple products. Reactive coloring components are inert into materials
which are adhered to the base substrate by the application of soda ash which act as fixing agent.
The main goal of our project is to provide information about the reason of using reactive dyestuff in
major textile industry in Bangladesh, different methods using in our industry for cotton dyeing with
reactive dyes, technical deficiency of reactive dyes during dyeing & causes and remedies of
deficiency of reactive dyes.
During reactive dyeing there is a rule of using different amount of soda ash with fixed amount of salt &
auxiliaries. In case of dyeing of cotton with reactive dyes alkali pH should be correctly maintained
as during dyeing more electrolytes required for exhaustion and alkali for fixation.
However the rubbing fastness and hand feel properties of dyed fabric depends on the amount of soda
ash. When we use fewer amounts of soda ash then hand feel is good but rubbing fastness is not
good. And when we use more amounts of soda ash then rubbing fastness is good but hand feel is
not good.
8. Chapter 4
INTRODUCTION
• With the evaluation of the wet processing industries the use of the reactive dyes in the most of the
industries increases day by day. As a result to complete the project it is has become a part to discus
about the evaluation or growth of the wet processing industries in Bangladesh. Now the number of
the wet processing industries and finishing industries in Bangladesh is 193 which are totally export
oriented according to the survey of the BTMA which has been provided into their we address.
• But the interesting matter is that with the growth of the textile wet processing mills the number of
the employee is not increasing. This is because of to reduce the cost and increase the quality the
modernization of the machine is also increasing which reduce the number of worker in wet
processing industries. But what is the actual number of the worker in wet processing industries has
not been found due to the lack of proper survey in this sector.
• Our project work was estimated as:
• APPLICATION OF REACTIVE DYES IN MAJOR TEXTILE IN BANGLADESH & DEFICIENCY OF REACTIVE
DYE:
• The project work is interesting as well as lengthy but we must admit that we had to really work
hard and it helps us a great deal to know about whole procedure of reactive dyeing on dyed fabric.
Though reactive dyeing products exhibit intrinsic characteristics which make them suitable for
multiple products application but reactive dye has it main problem with hydrolysis while dyeing as
a result wastage of the reactive dye increase and it become difficult to match the proper
9. The objects of project are:
Knowing the source of textile raw materials of wet
processing and cost.
To mention the reasons of using reactive dyes in major
textile industry.
To study on the application of reactive dyes
To learn about the technical deficiency of reactive dyeing.
To study the causes and remedy of deficiency of reactive
dyeing.
10. Chapter 5
RAW MATERIALS
• Raw material is a unique
substance in any production
oriented textile industry. It
not only plays a vital role in
case of continuous
production & for high
quality fabric but also it is
related to the profit of the
industry.
Types of raw material
• The basic raw materials
used in wet processing
industries are:
• Fabric
• Dyestuffs
• Chemicals & auxiliaries.
•
11. Names & source
Fabric:
Different types of fabric treated in Bengal Hurricane Group pvt Ltd. dyeing section are
namely
dyeing section
• Single Jersey
• Single jersey with Lycra
attachment
• Single Jersey with slub
• Double Jersey
• Polo pique
• Back pique
• Rib Fabric
• Flat back Rib
• Interlock
dyeing section
• Interlock with Lycra
• Pique
• Lacost
• Lacost Lycra
• Fleece
• Tery Fleece
• Waffle
• Melange
12. Fibres dyed:
By reactive dyes the
following fibres can be
dyed successfully:
1)Cotton, rayon, flax and
other cellulosic fibres.
2)Polyamide and wool
fibres.
3)Silk and acetate fibres
It covers a wide range of
color spectrum and
includes shades varying
from bright to heavy
dark like,
a. Violet
b. Blue
c. Green
d. Red
e. Black
f. Yellow
g.Etc.
13. Trade names
Some trade names of this dye are mentioned:
Trade name Manufacturer Country
Procion I.C.I U.K
Ciba cron Ciba Switzerland
Remazol Hoechst Germany
Levafix Bayer Germany
Reactone Geigy Switzerland
Primazin BASF Germany
Drimarine Sandoz Switzerland
14. Popularity of reactive dye:
Reactive are mostly used for dyeing cellulosic fibres. At past cellulosic fibres
were dyed with direct and vat dyes, but after the introduction of reactive
dyes there utility has become limited. Reactive dyes are superior to direct
dye in the following aspects:
i) Ability to procedure bright shades of wide range.
ii) High leveling quality.
iii) Good washing fastness.
iv) Good light fastness.
And it is superior to vat dyes in the following aspects:
i) Simple dyeing method therefore one stage dyeing.
ii) Low temperature dyeing (below 1000
C)
iii) Lower cost, i.e. cheaper.
Again its dyeing process is fast and gives brighter shades than metallized azo
dyes. For the above reasons reactive dyes are more popular.
15. NH (bridging part)
C
C C
N
Cl
N
N
-N N-
- NH
Hetreocyclic ring
The general structure of reactive dye is: D-B-G-X.
Chemical structure of reactive dyes
Here,
D= dye part or chromogen (color producing part)
Dyes may be direct, acid, disperse, premetallised dye etc.
B = bridging part.
Bridging part may be –NH- group or –NR- group.
G = reactive group bearing part.
X= reactive group.
16. Classification of reactive dyes:
Reactive dyes may be classified in various ways as below:
1) On the basis of reactive group:
a) Halogen (commonly chlorine) derivatives of nitrogen containing
heterocycle, like 3 types-
• Triazine group
• Pyridimine group
• Quinoxaline dyes
Example:
Triazine derivatives: procion, cibacron.
Pyridimine derivatives: reactone
Quinoxaline derivatives: levafix.
b)Activated vinyl compound:
• Vinyl sulphone
• Vinyl acrylamide
• Vinyl sulphonamide.
Example:
Vinyl sulphone: remazol
Vinyl acrylamide: primazine
Vinyl sulphonamide: levafix.
17. Classification of reactive dyes:
2) On the basis of reactivity:
a) Lower reactive dye:
Here ph is maintained 12-12.5 by using NaOH in bath.
b) Medium reactive dye: here pH is maintained 11-12 by using Na2CO3 in dye
bath.
c) Higher reactive dye: here pH is maintained 10-11 by using NaHCO3 in dye
bath.
3) On the basis of dyeing temperature:
a) Cold brand:
These types of dyes contain reactive group of high reactivity. So dyeing can be
done in lower temperature i.e. 320
-600
C.
For example: PROCION M, LIVAFIX E.
b) Medium brand:
This type of dyes contains reactive groups of moderate reactivity. So dyeing is
done in higher temperature than that of cold brand dyes i.e. in between 600
-710
C
temperatures.
For example, Remazol, Livafix are medium brand dyes.
c) Hot brand:
This type of dye contains reactive groups of least reactivity. So high temperature
is required for dyeing i.e. 720-930 C temperature is required for dyeing.
For example PRICION H, CIBACRON are hot brand dyes.
18. The reactive rate of some compounds are mentioned
below:
COMPOUND STRUCTURE REACTIVE RATE
Water H-OH 1.0
Iso-propanol CH3
-CHOH-CH3
0.7
Ethanol CH3
-CH2
-OH 7.4
Methanol H-CH2
-OH 12.3
Glucose C6
H12
O6
5.5
So from the above table it is obvious that secondary hydroxyl group is the beast reactive while
primary one is the most reactive.
19. Dyeing mechanism of reactive dye:
The dyeing mechanism of material with reactive dye takes place in 3 stages:-
1.Exhaustion of dye in presence of electrolyte or dye absorption.
2.Fixation under the influence of alkali.
3.wash-off the unfixed dye from material surface.
•Now they are mentioned below:
1.Dye absorption:
When fibre is immersed in dye liquor, an electrolyte is added to assist the exhaustion
of dye. Here NaCl is used as the electrolyte. This electrolyte neutralize the negative
charge formed in the fibre surface and puts extra energy to increase dye absorption. So
when the textile material is introduces to dye liquor the dye is exhausted on to the
fibre.
20. Dyeing mechanism of reactive dye:
2. Fixation:
Fixation of dye means the reaction of reactive group of
dye with terminal –OH or-NH2 group of fibre and thus
forming strong covalent bond with the fibre and thus
forming strong covalent bond with the fibre. This is an
important phase, which is controlled by maintaining
proper pH by adding alkali. The alkali used for this
purpose depends on brand of dye and dyeing
temperature. Here generally caustic soda, soda ash or
NaHCO3 is used as alkali depending upon reactivity of
dye. They create proper pH in dye bath and do as the
dye-fixing agent. The reaction takes place in this stage
is shown below:
21. alkali
pH10-12.5
1. D-SO2
-CH2
-CH2
-OSO3
Na + OH-Cell D-SO2
-CH2
-CH2
-O-Cell + NaHSO3
Alkali
2. D-SO2
-CH2
-CH2
-OSO3
Na + OH-Wool D-SO2
-CH2
-CH2
-O-Wool + NaHSO3
3.
3.
alkali
pH10-12.5
3. Wash-off:
As the dyeing is completed, a good wash must be applied to the material to remove extra
and unfixed dyes from material surface. This is necessary for level dyeing and good
22. Application method of reactive dyes varies significantly with type of dyes, shade
required, and available equipments in the mill. These are 3 application procedures
available:
1. Discontinuous method-
-Conventional method
-Exhaust or constant temperature method
-High temperature method
-Hot critical method.
2. Cotinuous method-
-Pad-steam method
-Pad dry method
- Pad thermofix method
3. Semi continuous method-
- Pad roll method
- Pad jig method
- Pad batch method.
23. Stripping of reactive dye:
1.Partial stripping:
Partial stripping is obtained by treating the dyed fabric with dilute acetic
acid or formic acid. Here temperature is raised to 70-100°C and treatment
is continued until shade is removed by desired amount. After that a
through washing is necessary to remove the product of hydrolysis. The
amount of acid used is as below: -
Glacial acetic acid : 5-10 parts
With water :1000 parts
Or
Formic acid :2.5 to 10 parts
With water :1000 parts
Temperature : 70 - 100°C
Time : until desired shade is obtained.
24. 2. Full stripping:
For complete stripping the goods are first treated with sodium
hydrosulphite (hydrose) at boil then washed off and bleached with 1%
sodium hypochlorite (NaOCl) at room temperature. This is carried out for
30 min. The recipe is as below: -
Na-hypochlorite : 1% at room
temperature
Na-hydrosulpite: at boil.
Time : 30 min
D-R-Cl + H-OH D-R-OH
+ H-Cl
•Hydrolysis of activated vinyl compound containing dye,
D-F-CH2
-CH2
-OSO3
H + H-OH D-F- CH2
-CH2
-OH + H2
SO4
For preventing hydrolysis the following precautions are taken—
1.As hydrolysis increases with increasing temperature during dissolving and
application temperature should not be more than 40°C.
1.Dye and alkali solution are prepared separately and mixed just before using.
2.Dye and alkali should not be kept for long time after mixing.
25. Important factors for dyeing cellulosic fibre with
cold brand reactive dye in batching process:
The important factors are as follows:
1) pH of the dye bath:
The optimum pH for fixing cold brand reactive dyes on cotton and viscose rayon depends on
individual dyes, the temperature and time of dyeing. pH decreases with increasing
temperature and time of dyeing. For most of the dyes the optimum pH is 10.8 to 11 at 20o
to
25o
C. Soda ash has been the best alkali for dyeing at 30o
C for cotton, mercerized cotton and
linen. Increased fixation (due to higher temperature) and increased dye bath stability and
better reproducibility are the advantages of soda ash as the fixing agent.
For viscose rayon the optimum pH is 10.3 at 20o
to 25o
C.
2) Amount of alkali:
The amount of alkali used for fixing depends on the depth of shade dyed and the liquor ratio
employed.Some quantities of alkali required for fixing the reactive dyes are given table 28.
3) Dyeing temperature:
Since increase in temperature affects the rate of physical and chemical processes involved in
dyeing, it is important in dyeing reactive dyes also. The affinity of the dye for the fibre
decreases with increases in temperature and at the same time the rate of hydrolysis of the
dye increases and adversely affects the fixation of color yield. However the rate of diffusion
of the dye in the fibre increases with increased temperature. At temperatures lower than
20o
c, the rate of fixation is very low. Hence for most of the dyes a temperature of 20o
to 25o
C
is the recommended temperature while for some other dyeing at 50o
to 60o
C with sodium
bicarbonate as the alkali gives maximum color value.
26. Important factors for dyeing cellulosic fibre with
cold brand reactive dye in batching process:
4) Electrolyte concentration:
Since reactive dyes have low affinity for cellulose exhausting the dye bath by
adding common salt or Glauber’s salt prior to fixation can increase the fixation. The
amount of salt required producing adequate exhaustion decreases with decreasing
liquor ratio. Thus for pale shade on cotton and viscose rayon 15 and 10 g/l of
common salt used. The quantities may be increased to 30 and 20 to 30 g/l for
medium and deep shades on these fibres.
5) Time of dyeing:
Generally the dye may be added in two portions. The salt may also be added in
two lots. The exhaustion takes place in 20 to 30 min. There is generally no
advantage in extending the period beyond 30 min. The alkali is then added and the
dyeing continued for 30 to 90 min. The depth of shade and reactivity of the dye
decide the time of dyeing. For deeper shades larger times are required.
6) Liquor ratio:
With decreased liquor ratio, both exhaustion and fixation take place to increased
exert. However the rate of fixation of most of the dyes is not significantly affected.
As the liquor ratio is decreased, the effectiveness of increasing salt addition also
decreases. Hence lower amount of salt are sufficient to get optimum exhaustion.
27. Why low affinity reactive dyes are preferred for dyeing?
• If the reactivity of the dye is increased considerably, the rate of reaction with the fibre
increases. There fore, the dyeing can be carried out in a short time. However in this case the
rate of dye also increases, leading to deactivation of a part of the dye. This results in
wastage of the dye. If on the other hand the reactivity of the dye is decreased, the extent of
hydrolysis can be reduced considerably. However this results in the slower rate of reaction
with the fibre also. The ultimate object of dyeing is to react as much of the dye ass possible
with the fibre and minimize the hydrolysis of the dye. This is achieved in practice in two
stages. The dyeing is first started from the aqueous medium under neutral conditions when
the dye does not react either with the fibre or with water. Then gluber salt or common salt is
added to exhaust the dye onto the fibre as much as possible. In this respect, this stage of
dyeing (exhaustion) resembles the dyeing of direct dyes on cotton. Then the second step (that
of fixation or reaction with the fibre) is carried out by adding the alkali (usually used soda
ash). Since the exhausted dye is already on the fibre, it is more likely that the exhausted dye
reacts with the fibre in preference to water. However the dye present in the dye bath (which
contains a substantial amount of the reactive dye) can now react with water since it is under
alkaline condition. It is already stated that the hydrolyzed dye cannot further react with the
fibre but dye to the affinity forces; it is absorbed by the fibre and is retained in it. During the
subsequent washing or soaping the substantivity held hydrolyzed dye gets stripped into the
treatment of the dyeing with boiling soap or detergent solution removes almost all
hydrolyzed dye. However if the affinity is very low, exhaustion of the dye bath prior to
fixation cannot be achieved substantially. This results in a larger amount of the reactive dye
remaining in the dye bath and getting hydrolyzed when alkali is added subsequently. If the
dye has high affinity for cellulose like a direct dye, it becomes difficult to remove the
hydrolyzed dye from the dyeing since it is also absorbed by and retained in the fibre by fairly
strong affinity forces, through not as strong ass the covalent bond formed between the dye
and the fibre. Hence in actual practice low affinity dyes are selected for converting in to
reactive dyes.
29. Brand name Type Source
Novolube Jet Anti creasing agent Techna,Italy
Bluton BVB1 Violet tone brightener CHT,Germany
Cibacel DBC Sequestering agent Ciba,India.
Cibafix ECO Fixing agent Ciba ,Switz.
Cibafluid C Anticreasing agent Ciba ,Switz.
SandocleanPCLF Detergent Clarient,Germany
Permacol FA Stabilizer Techna,Italy
Novostone CR Enzyme Techna,Italy
Cotton white T Redder tone brightener CHT,Germany
Cyclanon E Fixing agent BASF,Germany
Cyclanon ECO Reduction cleaning agent BASF,Germany
Jinlev RLF349 Dispersing agent Geigy,Taiwan
Eulysin S pH buffer in PET dyeing BASF,Germany
Felosan NOF Detergent CHT,Germany
Uvitex EBF Whitening agent Ciba ,Switz.
Jinlev CL-225 Levelling agent for reactive dye Geigy,Taiwan
Oxalic caid Iron remover -
Palegal FA-8 Levelling agent for disperse dye BASF,Germany
Respumit BU Antifoaming agent BASF,Germany
Permacol SQ Sequestering agent Techna,Italy
Na thiosulphate Peroxide killer -
Uniperol O Washing agent for PET dyeing BASF,Germany
Uvitex EVF PET brightener Ciba, Switz.
Uvitex 2B Yellow tone brightener Ciba ,Switz.
Mollan129 Soapinging agent Rota,dystar
Acetic acid pH controller -
Reduction HCS Reduction cleaning agent Geigy,Taiwan
Mollan130 Sequestering agent Rota,dystar
Bluton 2B Whitening agent Ciba,India
Chemicals:
30. • Remark
• The list is for the time of our industrial attachment. It
varies according to the availability of the material &
their price.
• The price has not been supplied to us due to their
secrecy act.
• The annual requirement was not available & is a record
of the procurement department.
31. Chapter 6
IMPORTANCE OF THE SURVEY
The main goal of our project is to provide information about the reason of using
reactive dyestuff in major textile industry in Bangladesh, different methods using
in our industry for cotton dyeing with reactive dyes, technical deficiency of reactive
dyes during dyeing & causes and remedies of deficiency of reactive dyes.
As these topics are very sensitive for dyeing industries, it is very much important to
make a survey. It will be very helpful not only for our studying period but also for
our future career.
This survey also has these importances:
1. To mention the reason of using reactive dyes in major textile industry.
2. To study on the application of reactive dyes.
3. To learn about the technical deficiency of reactive dyeing.
4. To study the causes and remedy of deficiency of reactive dyeing.
32. Chapter 7
Reason of using Reactive Dyes in Major Textile Industries in Bangladesh
Maximum textile industries in Bangladesh are based on cotton knit fabric and reactive dyes are easily
applicable to cellulose fibres.
Other associated reason as follows:
1. Reactive dyes are soluble in water.
2. They have very good light fastness with rating about 6.
3. The dyes have very stable electron arrangement and can protect the degrading effect of ultra-violet ray.
4. Textile materials dyed with reactive dyes have very good wash fastness with rating about 4-5 due to
strong covalent bonds formed between fibre polymer and reactive group of dye.
5. Reactive dyes give brighter shades and have moderate rubbing fastness.
6. Dyeing method of reactive dye is easy. It requires less time and low temperature for dyeing.
7. Reactive dyes are comparatively cheap.
8. Fixation occurs in alkaline condition.
9. Reactive dyes have good perspiration fastness with rating 4-5.
10. It has a wide range of shade
33. Chapter 8
Methods of Dyeing Cotton Goods with Reactive Dyes
Properties:
1. Anionic in nature.
2. Soluble in water.
3. Form strong covalent bond
4. Better wet & light fastness.
5. Have better substantivity.
6. Dyeing is carried out at alkaline condition.
Influencing factors:
1. PH
2. Temperature.
3. Conc. of electrolyte.
4. Time.
5. Liquor ratio.
REACTIVE DYE :
Reactive dye react with the fibres mainly react with cellulose fibres e.g. cotton, jute, bast fibres,
viscose, flax. It can be applied to protein fibres e.g. wool & silk. Reactive dye contains reactive
group and this reactive group makes covalent bonds with the fibres and becomes the part of the
fibre.
The general formula of reactive dye as follows:
D-X-Y
Here D->Chromophore of dye post
X->Bridge
Y->Functional group
D-X-Y + Fibre ->D-X-Y-Fibre Covalent bond
Reactive dyes water soluble
D-F + Cell-OH ->Dye-F-O-cell
D-F + H-OH ->Dye-F-OH
Hydrolysis
34. REACTIVE DYEING FOR SENSITIVE SHADE AT 60o
C
60min at 60O
C,
10min at 40-50O
C,
Dyeing:
Anticreasing Agent (.5 g/l)
Leveling Agent (1 g/l)
A. Acid ( .2 g/l)
Dyes (According to Shade %)
G. Salt (According to Shade %)
Soda Ash (According to Shade %)
Neutralization (Dyeing):
A. Acid (1 g/l)
Soaping:
Soaping Agent (.5 g/l)
Dyeing curve:
Sequestering Agent Color Dosing 600
C 50min
Leveling Agent Linear (30min) 500
C 10min
Bath drain
350
C 20min 30min 10min 10min 350
C Col
PH +Hardness Check Salt (15min) 1 g/l Soda Rest Soda w
(30min) (60min)
35.
HOT BRAND REACTIVE DYEING:
DYEING AT 92o
C:
60min at 80O
C, PH
= Above8
(Always)
10min at 40-
50O
C,
20min at 70-
80O
C,
15min at
40O
C,
20min at
40O
C,
Process steps:
Dyeing:
Anticreasing Agent (.5 g/l)
Leveling Agent (1 g/l)
A. Acid ( .2 g/l)
Dyes (According to Shade %)
G. Salt (According to Shade %)
Soda Ash (According to Shade %)
Neutralization (Dyeing):
A. Acid (1 g/l)
Soaping:
Soaping Agent (.5 g/l)
Fixing & Softening:
Fixing Agent (.5 g/l)
A. Acid (.5 g/l)
Softener (1.5 g/l)
Bath
Drain
36. Dyeing curve:
800
C 40min
Sequestering Agent Color Dosing 600
C 50min
Leveling Agent Linear (30min) 500
C 10min
Bath Drain
350
C 20min 30min 10min 10min 350
C Cold wash
PH +Hardness Check Salt (15min) 1 g/l Soda Rest Soda
(30min) (60min)
N.B: The temperature increase at the grade 10
C/min because
it’s an important matter to avoid the shade variation in dyeing
37. DARK COLOR DYEING WITH REACTIVE
DYE AT 600
CDyeing:
Anticreasing Agent (1.5 g/l)
Leveling Agent (1 g/l)
A. Acid (.2 g/l)
Dyes (According to Shade %)
G. Salt (According to Shade %)
Soda Ash (According to Shade %)
60min at 60O
C,
Neutralization (Dyeing):
A. Acid (1 g/l)
10min at 40-50O
C,
Soaping:
Soaping Agent (.5 g/l)
20min at 70-80O
C,
Fixing & Softening:
Fixing Agent (.5 g/l)
15min at 40O
C,
15min at 40OC,
A. Acid (.5 g/l)
Softener (1.5 g/l)
20min at 40O
C,
Bath Drain
60min at 60O
C,
10min at 40-50O
C,
20min at 70-80O
C,
20min at 40O
C,
15min at 40O
C,
38. Dyeing procedure for dark shade
Felosan NOF/Wetting agent = 0.5g/l
Kappazon H53NEU/Stabilizer (H2O2) = 0.5 g/l
Anticreasing agent = 1.0 g/l [Only for S/J]
↓ 60o
C x 5'
Caustic → 2 g/l
↓ 60o
C x 15'
Hydrogen peroxide → 2.5 g/l [Dosing 10']
↓ (60o
C - 80o
c)
Temperature rise up to 105o
C
↓ 30'
Acetic acid → 1.0 g/l
H2O2 killer → 0.5 g/l
↓ 60o
C x 10'
Acetic acid → 0.8 g/l (To control pH
= 4.5-5.5)
Enzyme → 1.5 g/l
↓ 55o
C x 45' - 60'
Kappaquest FE / Sequestering Agent → 0.35 g/l
↓ 90o
C x 5'
Sarabid LDR → 0.5 g/l (leveling agent)
↓ 60o
C x 5'
Gluber Salt (Runtime → 10')
↓ 60o
C x 10'
↓
Dye stuff
↓ 60o
C x 35' Runtime 20'
Soda ash
↓ 60o
C x 40' Runtime 60'
Bath drop after shade matching
↓
Hot rinse
↓ 60o
C x 10'
Soaping
↓ 80o
- 95o
C x 10'
Cold rinse
↓ 45o
C x 10'
Neutralize (Acetic acid = 0.5 g/l)
↓ 45o
C x 10'
Fixing
↓ 40o
C x 15'
Softening
↓
Unload
39. Dyeing Procedure for White
↓
Felosan NOF/wetting agent → 0.5 g/l
Kappazon H53NEU /Stabilizer → 0.5 g/l
Anticreasing agent → 1.0 g/l [Only for S/J]
Caustic → 3 g/l
↓ 60o
C x 15'
Hydrogen peroxide → 10.0 g/l
↓ 60o
C x 10'
Syno white 4BK/Optical brightener (60o
→
80o
C)
↓ 105o
x 60'
Acetic acid → 1.0 g/l
↓ NT x 10'
Acetic acid → 0.8 g/l [To Control PH
- 4.5 -
5.5]
Enzyme → 1.5 g/l
↓ 55o
C x 45' - 60'
Sequestering agent →
0.5 g/l
↓ 90o
C x 5'
Acetic acid → 0.35 g/l
Softener → 1.5 g/l
↓ 40o
C x 10'
N. Hot
↓
Unload
40. Dyeing procedure for Light/Medium Shade
↓
NOTE: - During Bleaching we maintain gradian to rise temperature from
80o
- 105o
C as 1.5o
/min and cooling from 105o
C - 80o
C as 2o
/min. For S/J
or low GSM. Fabric.
Felosan NOF/Wetting agent → 0.5 g/l
Kappazon H53NEU /Stabilizer (H2O2) → 0.5 g/l
Anticreasing → 1.0 g/l [Only for S/J]
↓ 60o
C x 5'
Caustic → 2 g/l
↓ 60o
C x 15'
Hydrogen peroxide → 2.5 g/l
↓ (60o
- 80o
C)
Temperature rise up to 105o
C
↓ 30'
Acetic acid → 1 g/l
H2O2 Killer → 0.5 g/l
↓ 60o
C x 10'
Acetic acid → 0.8 g/l [To Control PH
- 4.5 - 5.5]
Enzyme → 1.5 g/l
↓ 55o
C x 45'
Sequestering agent / Kappaquest FE → 0.35 g/l
↓ 90o
C x 5'
Sarabid LDR → 0.5 g/l (leveling agent)
• ↓
Anticreasing agent → 0.5 g/l [ For S/J]
↓ 60o
x 5'
Dye stuff
↓ 60o
C x 35' → Runtime → 20'
Glauber Salt
↓ 60o
x 10' → Runtime → 20'
Soda ash
↓ 60o
x 40' → Runtime → 60'
Bath drop after shade matching
↓
Hot rinse
↓ 60o
x 10'
Soaping
↓ 80o
- 90o
C x 10'
Cold rinse
↓ 45o
x 10'
Neutralize
↓ 45o
x 10'
Softening
↓
Unload
41. Dyeing procedure for S/J Light / Medium Color
↓Felosan NOF/ Wetting agent = 0.5 g/l
Kappazon H53NEU /H2O2 Stabilizer = 0.5 g/l
Anticreasing agent = 1.0 g/l
↓ 60o
x 5'
Caustic = 2 g/l
↓ 60o
C x 15' [Dossing]
Hydrogen peroxide (H2O2) = 2.5 g/l
↓ (60o
- 80o
C)
Temp rise up to 105o
C & Run - 30'
↓
Acetic acid = 1.0 g/l
H2O2 killer / Kappaquest FE = 0.5 g/l
↓ 60o
C x 10'
Acetic acid = 0.8 g/l [To control PH
- 4.5 - 5.5')
Enzyme = 1.5 g/l
↓ 55o
C x 45' - 60'
Sequestering agent = 0.35 g/l
↓ 90o
C x 5'
Sarabid LDR /Levelling agent = 0.5 g/l
Anticreasing - 0.5 g/l
• ↓
60o
x 5'
Dye stuff
↓ 60o
x 35' - Run time - 20'
Glauber Salt
↓ Dosing - 60o
x 10' - run time - 20'
Soda ash
↓ 60 x 40'
Bath drop after shade matching
↓
Hot rinse - 10' x 60o
C
↓
Soaping
↓ 80o
- 90o
C x 10'
Neutralization / Acetic acid
↓ 45o
C x 10
Cold rinse - 45o
x 10'
↓
Softening
↓
Unload
42. Migration Dyeing procedure for dark, medium & light shade
Felosan NOF/wetting agent → 0.5 g/l
Kappazon H53NEU /stabilizer (H2O2) → 0.5 g/l
Anticreasing → 1.0 g/l [Only for S/J]
↓ 60o
C x 5'
Caustic → 2 g/l
↓ 60o
C x 15'
Hydrogen peroxide → 2.5 g/l
↓ (60o
C - 80o
C)
Temperature rise up to 105o
C
↓ 105o
C x 30'
Acetic acid → 1.0 g/l
Kappaquest FE /H2O2 killer → 0.5 g/l
↓ 60o
C x 10'
Acetic acid → 0.8 g/l [To control PH
= 4.5 - 5.5']
Enzyme → 1.5 g/l
↓ 55o
C x 45' - 60'
Sequestering agent → 0.35
↓ 90o
C x 5'
Sarabid LDR → 0.5 g/l
Anticreasing agent → 0.5 g/l [for S/J]
↓
Dye stuff
↓ 60o
C x 35' → Run time - 20'
↓
Glauber Salt [Run time 10']
↓ 60o
x10'
Temperature rise up to 80o
C [ Run time→ 20']
↓ 80o
C x 20'
cooling to 60o
C
↓
soda ash
↓ 60o
C x 40' → Run time → 60'
Bath drop after shade matching
↓
Hot rinse
↓ 60o
x 10'
Soaping
↓ 80o
C - 95o
C x 10'
Cold rinse
↓ 40o
x 10'
Neutralize
↓ 45o
x 10'
Fixing [ For medium & dark shade]
↓ 40o
x 10'
Softening
↓
Unload
43. Sample (Dyeing)
COLOR RECIPE SAMPLE
BLACK SATAZOL YELLOW 3RS=1.649%
SATAZOL RED 3BS =O.912%
SATAZOL BLACK NNT=8.47%
RED KIRA.YELLOW HB=1.4%
KIRA. RED HB =2.0%
KIRA. RED SP2B=6.64%
MERUN KIRA.YELLOW HB=0.47%
KIRA. RED HB =3.8%
KIRA. BLUE HB =0.86%
DK-BLUE KIRA.YELLOW RR=0.188%
KIRA. RED RR =0.29%
KIRA. BLUE RR =1.26%
PINK SETA. RED 3BS =0.078%
SOLA.RED SP2B=0.02%
DK- TURGISH SATAZOL YELLOW 3RS=0.385%
SATAZOL RED 3BS =O.049%
SATAZOL BLUE BB=1.64%
44. Sample (Dyeing)
COLOR RECIPE SAMPLE
CLASSIC BLUE SATAZOL YELLOW 3RS=0.013%
SATAZOL RED 3BS =O.066%
SATAZOL BLUE SETR =0.62%
GOLD RUST SATAZOL YELLOW 3RS=3.14%
SATAZOL BLUE BB =O.004%
SATAZOL BLUE BB =0.40%
VIO-LET SATAZOL RED 3RS =0.65%
SATAZOL RED 3BS =O.48%
BZ. BLUE VW =1.40%
TURGISH E/B BLUE RSPL =2.1%
R/M T. BLUE G =0.6%
LIGHT YELLOW SETA. YELLOW 3BS=0.048%
RM. YELLOW 3GL =0.076%
NATURAL BEZ.YELLOW SLF=0.154%
BEZ.RED SLF =0.05%
BEZ.BLUE SLF =0.132%
DEEP LILAC E/B. YELLOW-4GL=0.008%
RED 3BSN =1.1%
BE. BLUE VRN =1.14%
45. Printing of cotton fabric with reactive dyes (block and screen
printing method), combination shade.
Introduction:
By the term textile printing we mean the localized application of dyes or pigment and
chemical by any method, which can produce particular effect of color on the fabric
according to the design. In this practical we print cotton fabric with cold brand
reactive dyes in block and screen-printing methods in combination method.
A dye, which is capable of reacting chemically with a substrate to form a covalent
dye substrate linkage, is known as reactive dye. The dye contains a reactive group
and this reactive group makes covalent bond with the fibre polymer and act as an
integral part of fibre. Reactive dyes forms covalent bond with fibre polymer and
thus attach itself with fibre. It is now a day mostly used for dyeing and printing of
cotton yarn and fabric. It is a cationic dye. Cold brand reactive dyes have higher
reactivity.
Block printing method is the oldest printing method. It is used mostly in sarees,
handkerchiefs etc. in this printing method we use blocks of different designs.
In screen printing a very little screen made by glass fibre is used. There are many
types of screen-printing, but we have done in our experiment was hand screen-
printing. Hand screen-printing is mostly used for sarees to 14-16 colors in on
pattern can be produced at a time.
46. Style of printing:
Direct style.
Method of printing:
Block and screen-printing method.
Sample:
One piece of square size bleached, scoured cotton fabric (small) and One piece of square size
bleached, scoured cotton fabric(bigger)
Combination color:
Total Dyes = 1.8gm
Blue = 0.6gm
Red = 0.6gm
Yellow = 0.6gm
Recipe:
Dye:
Total Dyes = 1.8gm
CIBA CRON RED = 0.6gm
CIBA CRON BLUE = 0.6gm
CIBA CRON YELLOW = 0.6gm
Urea = 8gm
Thickener = 70gm
Alkali = 8gm
Additional water = as required.
47. Preparation of thickener:
1)16 gm of starch and 200cc water are taken in
bowl.
2)Heat is applied and solution is stirred
continuously until a thick viscose solution is
obtained.
3)By continuous stirring and boiling a specific
viscosity is obtained.
4)The heat application is stopped otherwise
viscosity falls down. So temperature is
maintained strictly.
48. Preparation of printing paste:
1) At first we take required amount of dyestuffs in a bath.
2) Then little amount of water is added into the bath for
mixing these dyes. And start stirring for mixing the
three types of dye.
3) Then required amount of urea is added into the dye
bath.
4) After then required amount of thickener is added
5) Then continuous stirring is done for few minutes for
mixing all the ingredients of print paste.
6) After mixing finally required amount of alkali is added
to the dye bath and mix them with the help of stirring.
•
49. Printing process:
• Block printing method:
1)The fabric, which will be printed, is placed on the
printing table.
2)The printing paste is put on the tray box.
3)The block is selected and it is touched with print
paste.
4)Then block is pressed upon the sample fabric.
5)After pressing the block on the sample fabric the
block is put off from the fabric.
6)Finally we get the printed fabric of required dyes.
•
50. Screen-printing method:
1) The fabric is placed on the printing table of flat screen-
printing machine. The table is made of soft by laying
on it.
2) Then the screen is placed on the sample fabric.
3) The printing paste is taken on the screen perforation.
4) Thus we can find the printed fabric with a smooth
wooden strike the paste is spread over the screen with
slight pressure.
5) So that the dye particles can penetrate through the
screen perforation.
6) Thus we get printed fabric.
•
51. After treatment:
• The printed fabric is steamed for 5-10 minutes
in a cottages steamer at 1050
-1100
C and washed
with cold water for removing unfixed dye and
exhausted thickener and then dried.
52. Conclusion
Printing of cotton fabric with reactive dyes has
excellent build up property and maximum
fixation. Shade is also bright. By this
experiment we have acquire knowledge about
process of printing cotton fibres with cold
brand reactive dyes in combination shade. The
shade of printed fabric is moderately good, as
we required. Special thanks to our teacher and
his assistants for grate cooperation.
•
53. Chapter 9
Technical Deficiency of Reactive Dyes, CAUSES AND THEIR
REMEDIES
•
• Hydrolysis is the main problem in dyeing with
Reactive dyes. Only 60 to 70 percent dyes are
absorbed in Reactive dyeing. There are also
many causes of technical deficiency of
reactive dye. Those are described below:
54. Hydrolysis of reactive dyes:
Under alkaline condition, reactive dyes react with the terminal hydroxyl group of
cellulose. But if the solution of the dye is kept for long time, it’s concentration drops.
Then the dye react with the hydroxyl group of water .The reaction of dye with water is
called Hydrolysis of reactive dyes.
55. Factors which affect the hydrolysis of the reactive dye:
1. Salt concentration:
When the cellulosic textile material is sink into water it convert into negetive charge or anionic
charge. But the reactive dye is also convert into anionic charge. So the surface of the cellulosic material repel
the dye molecules. To overcome the problem we use electrolite material like salt. It hepls to netralize the
negetive ion over the textile material and helps the reactive dye ion to fix on the surface of the materail. As a
result If we increase the concentration of the salt hydrolysis of the reactive dye will decrease.
2.pH:
if the pH of the medium increase hydrolysis of the reactive dye also increase. This is for, reactive dye
ionised more in alkaline medium and as a result it react with hydroxyl group of the water.
3.Temperature:
With the increase of temperature hydrolysis of the reactive dye increases.
4.Substantivity:
With the increase of the substantivity hydrolysis of the reactive dye increase.
5.Reactive group of the reactive dye:
Hydrolysis of the reactive dye depends on which group does it bears. Vinyl sulphone dye hydrolyize
more than the Triazinyl group.
56. Factors which affect the hydrolysis of the reactive dye:
Hydrolysis of water:
Hydrolysis of the water is also a cause of
the technical deficiency of the reactive dye.
Remidies of the hydrolysis of the reactive dyes:
The highest absorption of the reactive dye is
about 70%. To minnimize the more lose of the reactive
dye we should maintain proper liquor ratio, proper
time and temperature. Even the pH of the emdium is
also an important factor to avoid the more wastage of
the reactive dye
57. Faults and their remedies for the technical deficiency of reactive dyes:
• There creates many problems and defects in dyed fabrics when dyeing with Reactive dyes due to
technical deficiency. Some defects may be remedied by some process. Those are described below:
•
• Defect: Colors are not fast to washing, Abrasion; Staining in the fabric when transporting from
place to the other, water marks on the fabric
Remedy : Wash the fabric with soap and soda ash at right temperature. Adding sequestering agent
will yield good results. Treating with Ammonia will also give good results.
Defects in the fabric due to Printing- Need to take out full color
Remedy: Treat the dyed fabric with Sodium Hydrosulphite with 5-10 gm Sodium Hydrosulphite at
75 deg C for 30-45 minutes. Add 5-7 gms Caustic Soda for even removal of colors. The color
becomes light yellow or brown after removal. Wash it thoroughly with soap.
The color can also be removed by solution of Sodium Hypochlorite. Treat the fabric with a sodium
hypochlorite solution ( 3-5 gms Chlorine) for 20-30 minutes. Keep the pH between 9-10. The fabric
is treated with Acetic acid after removal of color to remove chlorine and to neutralize the fabric.
The fabric can be re-dyed after removal of color
58. Faults and their remedies for the technical deficiency of
reactive dyes:
• Defect: Bleeding in colors during washing, abrasion
Remedy: Boil the fabric with caustic, Treat the fabric with Hydrogen Peroxide ( 5-10 gpl, 60-70 deg C) to make the color fast.
Defect: The fabric has been dyed in darker shade, uneven dyeing
Remedy: To take out color from the fabric treat it with caustic for 45-60 min at 70 deg C. Thereafter treat the fabric with 10-20 gpl
Acetic Acid for 40-60 min at 80-85 deg C.
Defect: Uneven dyeing, marks of water, marks of colors
Remedy: Wash the fabric in soap and re-dye in a darker shade
Defect : The fabric has become stiff and rough after dyeing
Remedy: Finish after adding right softener
Defect: Color staining of fabric, uneven dyeing
Remedy: Re-dye the fabric in darker shade.
Defect: Color staining in fabrics of darker shade, uneven dyeing.
Remedy: Dye the fabric in Sulphur black.
• Caution: Please treat a small length fabric to check the effectiveness and any harmful effects before commencing a full treatment.
•
• Defect: Color staining of fabric, uneven dyeing
Remedy: Re-dye the fabric in darker shade.
59. Chapter 10
Conclusion
Obviously the project work we have discussed has many other arguments but as far as
we believe the presented view to a large extent is one that has a predominant role
in our textile sector especially in REACTIVE DYEING & thus has the ability to
influence our thoughts.
REACTIVE DYEING is truly an important dyeing phenomenon for cellulose materials &
ranks as the major contribution to the progression of any textile dyeing industry.
Dyeing parameters have a great influence on reactive dyeing which have described
in my report. It was really an important subject & also innovative one. I have tried
my best to express the topics properly.
The project work has given us a special interest & has been arranged as a presentation
of the application reactive dyes in cotton dyeing. I think anyone can research in
future about this topic which will enrich our textile knowledge.
Any absolute conclusion is impossible but waiting the pros & cons I’m certain that my
position is a tenable one.