Topics Name

Comparative study between bio scouring bleaching and traditional scouring and bleaching and cotton fabric dyeing with reactive dye.

IntroductionTheoretical FoundationsExperimental Techniques & MethodologyResult & DiscussionConclusion

Topic Sequence

Now a days, it is becoming important to consumers that the clothes they buy are well made and of high quality material. Additionally, a growing number of consumers are also interested in clothes that are produced in an environmentally friendly way without the extensive use of harsh chemicals. Enzymatic Scouring or Bio-Scouring can simply be defined as the application of living organisms and their components to remove the natural and added impurities. It is not an industry in itself, but an important technology that will have a large impact on many industrial sectors in the future. Bio Scouring firms will rely mainly on inexpensive substrates for biosynthesis, processes that will function at low temperatures, and will consume little energy and water as well. In Textile Processing the Enzymatic removal of impurities also reduces the total chemical consumptions and possibilities of accident.

Introduction

Cotton Cotton is a soft, fluffy staple fiber that grows in a boll, or

protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal. The plant is a shrub native to tropical and subtropical regions around the world, including the America, Africa, and India. The greatest diversity of wild cotton species is found in Mexico, followed by Australia and Africa. Cotton was independently domesticated in the Old and New Worlds. The English name derives from the Arabic (al) qutn نْط,ن, which began to be ,ُقused circa 1400 AD.

Theoretical Foundations

Theoretical FoundationsTypes of cotton:There are four commercially-grown species of cotton, all domesticated

in antiquity:Gossypium hirsutum – upland cotton, native to Central

America, Mexico, the Caribbean and southern Florida, (90% of world production)

Gossypium barbadense – known as extra-long staple cotton, native to tropical South America (8% of world production)

Gossypium arboreum – tree cotton, native to India and Pakistan (less than 2%)

Gossypium herbaceum – Levant cotton, native to southern Africa and the Arabian Peninsula (less than 2%)

Leading producer countries:

Top ten cotton producers—2011 (480-pound bales)

People's Republic of China 33.0 million bales India 27.0 million bales United States 18.0 million bales Pakistan 10.3 million bales Brazil 9.3 million bales Uzbekistan 4.6 million bales Australia 4.2 million bales Turkey 2.8 million bales Turkmenistan 1.6 million bales Greece 1.4 million bales

Reactive dye

A dye, which is capable of reacting chemically with a substrate to form a covalent dye substrate linkage, is known as reactive dye. Here 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. This covalent bond is formed between the dye molecules and the terminal –OH (hydroxyl) group of cellulosic fibres on between the dye molecules and the terminal –NH2 (amino) group of polyamide or wool fibres.

Which Fibers can be dyed with Reactive Dye:

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.

General Features of a Reactive Dye:

Molecule

W = water solubilising groupD = chromophoreB = bridging groupRG = reactive groupX = leaving group3

W

D B RG ------X

Principles Structure of Reactive Dye

Advantages:Full Color GamutBrilliant, bright colorsCovalent fixation, high Wash Fastness (WF)Varying reactivitiesVarious temperatures including low energy (cold

dyeing)Various methods of applicationInexpensive to apply (but dyes expensive)

Disadvantages:

Incomplete fixation (problem with hydrolysis)Need for wash-off (for high WF)Need for high concentrations of salt affect natural balance

of watercoursesHigh pHSome dyes are “AOX” – potentially harmful to the

environment

BIO SCOURING:

To create high-quality end-products, the manufacturing process must be of high quality. That is why a good way to start the elemental textiles process off right is to begin with a natural enzymatic bio-scouring the sustainable alternative to harsh scouring.

Advantages of Bio-Scouring over Traditional scouring:

The advantages of bio scouring comparing to traditional scouring can be found in all of the following perspectives----

Quality perspectiveEconomic perspectiveEnvironmental perspective

Experimental Techniques & Methodology

Bio-scouring & Bleaching Experiment:

To find out the suitable effect of Bio-scouring, we do the experiment of bio-scouring at different concentration same pH and temperature. The amount and calculation of the chemicals are described below:

Recipe for Bio-scouring & Bleaching:

Fabric weight= 12.15gm Anti creasing agent=1g/l Bio-Scouring = 2,3,4 g/l Detergent = 0.5g/l Sequestering agent = 0.25g/l Stabilizer = 0.8g/l Ammonia buffer =2ml/l

H2O2= 2,3,4 g/l, Detergent = 0.5g/l H2O2 Killer=0.2g/l Acetic Acid= 0.5g/l L:R = 1:30 Temperature= 900C Time= 30min

Bio- scouring & bleaching curve:

1

30° c

21 3 4 6 75

30 min

90 ° c

Drained

8.9 10

60 ° c 80 ° c

10 min10 min

DrainedDrained

Traditional Scouring & Bleaching:Recipe:Detergent = 0.5g/l Sequestering agent = 0.25g/lStabilizer = 0.5g/lNaOH =2,3,4 g/lH2O2= 2,3,4 g/lAnti creasing agent=1g/lH2O2killer = 0.2g/l Acetic Acid= 0.5ml/lDetergent=0.5g/lFabric weight= 12.15gmL:R = 1:30 Temperature= 1000C Time= 30min

Traditional scouring & bleaching curve:

1

30° c

21 3 4 65

30 min

100 ° c

Drained

7,8 9

60 ° c 80 ° c

10 min10 min

DrainedDrained

Weight Loss%:The actual wt. of the sample and after scoured sample

wt. difference is wt. loss %. The wt. of the scoured sample is less than un-scoured

sample.Standard wt. loss% is 4-8%. If it is 5% then we may say

that the sample is well scoured but if it is ›5% then it is not acceptable as it means the fiber damage has taken place. If it is ‹4% then the sample is not well scoured and there are impurities still present in the sample.

Absorbency Test:

Immersion Test Drop Test and Wicking Test

Immersion Test:

A sample is more absorbent it is more scoured.(1cm*1cm) sample is placed on a water surface and time taken by it to be immersed is noted. The standard time is 5s. if it is up to 10s we may say that the sample is well scoured. If it is >10s then the scouring has not taken place properly.

Drop Test: In This test, colored solution of 0.1% direct dye (Red) is used.

The solution is dropped on to the sample by pippet and its absorbency is estimated visually. The drop may have various shapes when absorbed.

Two things can be measured: The time is taken is s to absorb one drop of solution. Standard

time is 0.5sto 0.8s, up to 1s is allowed. But in this test some errors are bound to creep in because the time taken for absorption is very little and absorbency is estimated visually. It may vary from person to person’s perception.

If the drop is circularly absorbed, then we say that sample is very uniformly scoured. If drop is circular but has small area, then the sample is uniformly scoured. If it is almost circular then it is uniformly scoured too. If it is not circular then it is not uniformly scoured.

Wicking Test:

A 5cm*18cm sample is taken and a mark is made at the 1cm from bottom. Then 1cm portion is immersed into 1% direct dye solution for 5 min and then the distance traveled by the colored solution about 1cm mark is noted. The acceptable range is 30-50mm.

Dyeing Process Bio scoured-bleached fabric:

Recipe:Fabric weight=10gm Reactive dye = 1%Sequestering agent = 0.25g/lGlauber salt=30g/lNa2CO3=10g/lAcetic Acid= 0.5g/lSoap=2g/lTemperature= 600CTime=60minL:R = 1:30

Dyeing curve:

1

30° c

1 260 min

60 ° c

Drained

5 6

60 ° c 90 ° c

10 min10 minDrainedDrained

3

4

Rubbing fastness (Crock meter):The test determines the fastness of a dyestuff to either dry

or wet rubbing. For testing, the sample is cut 15 cm length and 5 cm width. The specimen is placed on the base of the crockmeter sand a square of white test cloth is rubbed on to the colored sample by means of crockmeter finger. The white test cloth has to be cotton which is desized-bleached but without finished. In case of dry test condition, the white test cloth is directly attached to the top of the crockmeter finger. In case of wet test condition the crocking cloth is wetted with distilled water and is rubbed 20 times by to and for movement 91 rub/sec) in 10 cm long by turning the handle. The test is done both for warp for warp and weft direction.

Color Fastness to Wash:

Principal of Wash Fastness: A specimen/dyed material with specified adjacent fabric (MFF) are laundered rinsed and dried. The specimen/composite sample is treated under appropriate condition in a chemical bath for recommended time. The abrasive action is accomplished by the use of a liquor ration and an appropriate number of steel balls. The change in color of the specimen (dyed sample) and the staining of the adjacent fabric (MFF) is assessed by recommended grey scales (1-5).

Results & DiscussionsTable: 01 Variation in concentration for bio-scouring & bleaching (Weight loss%)

Sample no.

Concentration of

Temp. °c Weight (gm) (Before)

Weight (gm) (After)

Weight loss %

Bio-S H2O2

1 2g/l 2g/l 90°c 12.15 11.81 2.8%

2 3g/l 3g/l 90°c 12.15 11.80 2.9%

3 4g/l 4g/l 90°c 12.15 11.70 3.7%

Results & DiscussionsTable: 02 Traditional Scouring and Bleaching (Weight loss %)

Sample no.

Concentration of

Temp. °c Weight (gm) (Before)

Weight (gm) (After)

Weight loss %

Caustic Soda

H2O2

1 2g/l 2g/l 90°c 12.15 11.85 2.5%

2 3g/l 3g/l 90°c 12.15 11.83 2.6%

3 4g/l 4g/l 90°c 12.15 11.75 3.3%

Comparison between Bio-Scoured bleached & Conventional scoured Bleached Wt. loss %

Comparison between Bio-Scoured bleached & Conventional scoured Bleached Immersion Test (in sec)

Comparison between Bio-Scoured bleached & Conventional scoured Bleached Drop Test (in sec)

Absorbency Test of Bio and Traditional Scouring and Bleaching Sample DropTest

Serial No. Bio Scouring Bleaching Sample

Traditional Scouring Bleaching Sample

1

2

3

Comparison between Bio-Scoured bleached & Conventional scoured Bleached Wicking Test (in sec)

Absorbency Test of Bio and Traditional Scouring and Bleaching Sample Wicking Test

Serial No. Bio Scouring Bleaching Sample

Traditional Scouring Bleaching Sample

1

2

3

Rubbing Fastness (Wet and Dry) Bio Scoured-bleached

Serial No. Direction Dry Rub Wet Rub

01 Warp Way 4/5 4/5

02 Warp Way 4/5 4/5

03 Warp Way 4/5 4/5

04 Weft Way 4/5 4/5

05 Weft Way 4/5 4/5

06 Weft Way 4/5 4/5

Rubbing Fastness (Wet and Dry) Conventioanal Scoured-bleached

Serial No. Direction Dry Rub Wet Rub

01 Warp Way 4/5 4/5

02 Warp Way 4/5 4/5

03 Warp Way 4/5 4/5

04 Weft Way 4/5 4/5

05 Weft Way 4/5 4/5

06 Weft Way 4/5 4/5

Color Fastness to Wash:Test Description Result

Color fastness to wash (ISO-105-C03) Grade

Color change in shade staining in Acetate 4/5

Color change in shade staining in Cotton 4/5

Color change in shade staining in Polyamide 4/5

Color change in shade staining in Polyester 4/5

Color change in shade staining in Acrylic 4/5

Color change in shade staining in Wool 4/5

Color Fastness to Wash:Tested Sample 1 Multi Fiber Fabric Wash

ConclusionBio-Scouring & Bleaching process is also called Eco-friendly

Scouring & Bleaching .This process is applied to cellulose textiles that produces permanent effects by the use of enzymes. Bio-Scouring & bleaching removes protruding fibers and slubs from fabrics by the use of enzymes, significantly reduces, softens fabric hand and provides a smooth fabric appearance, with high whiteness especially for knitwear.

Wash fastness of the enzyme treated sample before dyeing is very poor but after dyeing is very good. Lastly we can say that this is a very important topic through which we have learned more about Bio-Scouring-Bleaching treatment.

The electric shortage, in our country drove people to use energy saving technology and the water pollution caused by textile effluents, particularly from pretreatment ,leaves dye houses no alternative but to choose an environmentally friendly process .it is not clear why bio process has not yet been widely accepted by industries .But we can say that ,it is only a matter of time that the drawbacks will be conquered and it will be the future of textile processing.