Performance Analysis of Denim Garments by Bleach Wash

Last Updated on 22/03/2021

Performance Analysis of Denim Garments by Bleach Wash

Md. Anwarul Haque1
Ariful Hassan2
Shantonu Paul Shuvra 
Md. ShagorHossain &
Zakia Sultana

Textile Engineering College, Noakhali.
Email: haquebd2014@gmail.com1, arifulhassan034@gmail.com2

 

Abstract:
Change of appearance of denim garments by washing was investigated using bleach treatment. The effect of various temperature and time, concentrations of bleaching powder on the degradation of denim fabrics were evaluated by means of fabric strength loss, stiffness, GSM, color fading, elongation at break, moisture absorption, change of EPI-PPI, crimp, shrinkage. It was found that bleaching powder had remarkable effect in washing on denim fabric modification. It was also observed that the degradation of denim fabric with bleach caused a serious drop in fabric strength, stiffness, color fading.

Introduction:
Denim is very strong, stiff and hard-wearing woven fabric. Denim is cotton and twill weave fabric that uses colored warp and white weft yarn and used for jeans, work clothes and casual wear. Denim garments washing is known as one of the widely used finishing treatment that has vast usage in textile sectors because of creating special appearance and making fashionable and wear comfortable garments of the present-day world and commonly used. Without finishing treatments, denim garments are uncomfortable to wear, due to its weaving and dyeing effects. For this it essentially needs a finishing treatment to make it softer, more supple, smooth and comfortable to wear performance. Popularity of garments washing specially on denim garments in the World market has been increasing day by day. To meet up the quick change of current demands of customers, technologists are trying to introduce new designs and fashion on denim garments by using different washing methods.

The most commonly denim washing methods are bleach wash, acid wash, enzyme wash, normal wash, stone wash, etc. Among the washing methods, bleach method is widely used method in industry especially for denim washing to achieve required color shade by hypochlorite bleaching. Bleaching treatments have been successful for achieving desirable color shade and soft hand feels of cotton denim garments and are using in textile and washing industry. However, cellulase enzyme treatments have been successful at improving flexibility and soft hand feels of cotton denim garments but it degrades cellulose at the end or in the middle of the cellulose chain, yielding shorter chain cellulose polymers, and reduces its mechanical strength. So, denim washing using bleaching powder is chosen for this work.

Many researchers have investigated the washing of denim garments using various methods for the last many years but a few works have been done on washing of denim garments to develop novel design and fashion with high wear performance by bleach method. Bangladesh is a textile industry-based country. Denim garments (trousers) are being produced with other garments to meet its demand in the competitive market of world and Bangladesh earned about 76% foreign currency from ready-made garments sector. In this paper, a novel and cost-effective method have explored for denim washing with bleaching powder that developed new design and fashion and is produced a value-added product with high wear performance to satisfy customer’s need. In addition, the effects of washing parameters on the physical and mechanical properties of treated denim garments have investigated.

LITERATURE REVIEW

History of denim
In fashion history, jeans and denim history continues to baffle. No one truly knows the perfect answer to where jeans began. As so often happens fashions often emerge together in various parts of the world and are the result of the sudden availability of anew fabric, cloth, dye or technique. But we do know that the phrase denim jeans are thought to derive from several sources. No one is totally certain where the words come from. A majority of source books suggest that denim derives from the English translation of the South of France French phrase ‘serge de Nimes’. Denim fashion history is thus associated with Serge de Nimes. When talking about denim the name Levi´ s is one of the first to be mentioned. Levi´ switch stands for Levi Strauss are normally called the forefather of jean.

When Tracing back the history of these trousers to its origins it is true that Levi Strauss played an important role concerning their development and distribution but he had also other inventive business partners Levi Strauss found out that the gold diggers´ hard work in the mines made their clothes get worn out very quickly and he produced stout working trousers out of the sail cloth he had taken with him which he called half overalls“. When he continued producing these.

Trousers he used cheap cotton fabrics coming from Geneva. The name of the town of Geneva was modified into jeans” in the American slang. At the end of the sixties of the19th century he replaced the brown sail cloth by an indigo-dyed, wear resistant cotton fabric coming from France. The name of this fabric was Sergede Nimes “. Serge is the French. Expression for a combined twill and Nimes is the French town where the fabric comes from. The fabric´s name Serge de Nimes was quickly turned into Denim in American colloquial language.

By applying this indigo-dyed combined twill the first jeans out of Denim was almost born or better sewn. The application of metal rivets for jeans is due to the Polish emigrant Jacob W. Davis, also called A Jacob Youphes. Although the working trousers out of Denim were stout they had a tendency to get worn-out where the pockets were. Jacob Youphes mended the trousers with a needle and thread. One day a customer inspired him to repair the torn off pockets with the help of rivets. Under the management of Levi Strauss, the jeans were now produced in series. Since the trousers were so stout not only the gold diggers liked them but which is not surprising in America? The cowboys appreciated them very much, too. When the trousers were applied as working trousers for cowboys, however they got worn out at the crotch tip. This was no problem for Levi Strauss and Co. since they reinforced the trousers again with metal rivets at the crossing point of the four seams at the crotch tip. About 1947 denim made a break-away from work clothing image, chiefly in the area of sportswear and rainwear and an occasional appearance in high fashion collections as a “different-looking” evening dress. In 1970 American youth adopted denim as their favorite fabric. Part of a “back to nature” movement that emphasized ecology and the natural denim being a fabric created from a natural fiber was a primary factor. Since 1960the jeans business has undergone an explosive transformation, from a source of tough, cheap clothing for cowboys, blue-collar workers and penniless youth into a fashion-conscious market for a widening mass of people of almost all ages.

Types of Denim
While the original denim was a 100% cotton serge material, we can now get it in a variety of materials, including blends that give you the same wonderful look of 100% cotton denim with some great additional features. Denim’s unique look comes from the rich indigo blue in one shade or another woven together with white threads to give the “depth” that people associate with denim. Today, some denims no longer have indigo, but other colors with the white opposing threads, producing denims in a rainbow of shades.

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Types of Denim are given below:

1. Dry Denim

Dry Denim
Fig: Dry Denim

2. Selvage Denim

Selvage Denim
Fig: Selvage Denim

3. Stretch Denim

Stretch Denim
Fig: Stretch Denim

4. Poly Denim

Poly Denim
Fig: Poly Denim

5. Ramie Cotton Denim

Ramie Cotton Denim
Fig: Ramie Cotton Denim

Flow Chart of Denim Production:

Spinning

Bale Warping

Rope Dyeing

Long Chain Beaming

Sizing

Weaving

Finishing

Inspection & Folding

Packing

Dispatch

Denim Products

Clothing:

  1. Boots and athletic shoes
  2. Capri pants
  3. Dresses
  4. Hats
  5. Jackets
  6. Jeans
  7. Overalls (dungarees)
  8. Shirts
  9. Shorts, including Daisy Dukes and cut-offs
  10. Skirts
  11. Sneakers (Keds, Converse Chuck)
  12. Suits
  13. Swimsuits

Accessories:

  1. Belts
  2. Handbags (purses)
  3. Tote bags
  4. Furniture:
  5. Bean bag chairs
  6. Lampshades
  7. Upholstery

Vehicles:
Between 1973 and 1975 Volkswagen produced the Jeans Beetle, which had all-denim trim. They also repeated this concept in some later models. AMC offered a Levi’s trim package for its Gremlin and Pacermodels, which actually spun nylon was made to imitate denim. Jeep has also offered Levi’s trim packages.

Bleaching
Bleaching is chemical treatment employed for the removal of natural coloring matter from the substrate. The source of natural color is organic compounds with conjugated double bonds, by doing chemical bleaching the discoloration takes place by the breaking the chromospheres, most likely destroying the one or more double bonds with in this conjugated system. The material appears whiter after the bleaching.

Natural fibers, i.e. cotton, wool, linen etc. are off-white in color due to color bodies present in the fiber. The degree of off-whiteness varies from batch-to-batch. Bleaching therefore can be defined as the destruction of these color bodies. White is also an important market color so the whitest white has commercial value. Yellow is a component of derived shades. For example, when yellow is mixed with blue, the shade turns green. A consistent white base fabric has real value when dyeing light to medium shades because it is much easier to reproduce shade matches on a consistent white background than on one that varies in amount of yellow.

Bleaching may be the only preparatory process or it may be used in conjunction with other treatments, e.g. desizing, scouring and mercerizing. The combination of such treatments for an individual situation will depend on the rigorousness of the preparation standard and economic factors within the various options. Other chemicals will be used in addition to the bleaching agent. These serve various functions such as to activate the bleaching system, to stabilize or control the rate of activation, to give wetting and detergent action, or to sequester metallic impurities. This section gives consideration to the selection of bleaching agents and to the role of the various chemicals used in conjunction.

The purpose of bleaching is to remove coloured impurities from the fibre and increase the whiteness level of fabric.

Manufacturing of Bleaching Powder
The manufacture of bleaching powder is carried out in Backmann’s plant as follows:

It consists of a vertical cast-iron tower. The tower is provided with a hopper at the top, two inlets near the base (one for chlorine and other for hot air) and an exit for waste gases near the top.

Bleaching powder
Fig: Bleaching powder

The tower is fitted with eight shelves at different heights each equipped with rotating rakes. The slaked lime is introduced through the hopper and it comes in contact with chlorine, which slowly moves upwards. Bleaching powder is collected in a barrel at the base. The chlorine used in the manufacture of bleaching powder should be dilute and the temperature should be maintained below 40oC.

Mechanism of bleach action
Color in most dyes and pigments are produced by molecules, such as beta carotene, which contain chromospheres. Chemical bleaches work in one of two ways:

Oxidizing bleach works by breaking the chemical bonds that make up the chromosphere. This changes the molecule into a different substance that either does not contain a chromosphere, or contains a chromosphere that does not absorb visible light.

Reducing bleach works by converting double bonds in the chromosphere into single bonds. This eliminates the ability of the chromosphere to absorb visible light.

Chemical interactions
Mixing hypochlorite bleach with an acid can liberate chlorine gas. Hypochlorite and chlorine are in equilibrium in water; the position of the equilibrium is pH dependent and low pH (acidic) favors chlorine.

Cl2 + H2O → H+ + Cl− + HClO

Chlorine is a respiratory irritant that attacks mucous membranes and burns the skin. As little as 3.53 ppm can be detected as an odor, and 1000 ppm is likely to be fatal after a few deep breaths. Exposure to chlorine has been limited to 0.5 ppm (8-hour time-weighted average—38-hour week) by OSHA in the U.S.

Sodium hypochlorite and ammonia react to form a number of products, depending on the temperature, concentration, and how they are mixed. The main reaction is chlorination of ammonia, first giving chloramine (NH2Cl), then dichloramine (NHCl2) and finally nitrogen trichloride (NCl3). These materials are very irritating to the eyes and lungs and are toxic above certain concentrations; nitrogen trichloride is also a very sensitive explosive.

NH3 + NaOCl → NaOH + NH2Cl

NH2Cl + NaOCl → NaOH + NHCl2

NHCl2 + NaOCl → NaOH + NCl3

Additional reactions produce hydrazine, in a variation of the Olin Raschig process.

NH3 + NH2Cl + NaOH → N2H4 + NaCl + H2O

The hydrazine generated can react with more chloramine in an exothermic reaction to produce ammonium chloride and nitrogen gas:

2NH2Cl + N2H4 → 2NH4Cl + N2

However, the place of atomic oxygen in accounting for the formation of chlorine is not as plausible as another theory based on the so-called ‘chloride system’ employed in modern hydrometallurgy to dissolve ores with weak acids in highly ionic and concentrated salt solutions. Salts particularly effective, in this regard, include MgCl2, CaCl2, FeCl3 and, to a lesser extent, the mono-valent NaCl. This is, in effect, an application of the non-common ion theory, or as discussed in Wikipedia under Solubility Equilibrium as the ‘salt effect’. With respect to bleaching powder, which has been described as a compound salt of the form Ca(ClO)2.CaCl2.Ca(OH)2.xH2O, the presence of CaCl2 in very concentrated solutions can greatly increase the ‘activity level’ of weak acids. So, in this particular proposed application, H2CO3 from CO2 and moisture on the bleaching powder, acts on the CaCl2 to release some HCl which acts on the HClO releasing Chlorine:

HClO + HCl → H2O + Cl2

or, the increasing acidity creates more HClO which moves the following known (and old, see Watt’s Dictionary of Chemistry) equilibrium reaction to the right:

CaCl2 + 2HClO = Ca(OH)2 + 2Cl2

Properties of the Bleaching powder

1) Bleaching powder is yellowish in color and white powder and smells chlorine.

2) Bleaching is soluble in water. The lime present is left behind as an insoluble salt so it is called chloride of lime.

3) When Bleaching powder is exposed to air, it is oxidized to chlorine.
CaOCl2 + CO2———> CaCO3 + Cl2

4) Chlorine gas is produced, when Bleaching powder is treated with excess of dilute acid.
CaOCl2 + H2SO4 (dilute) ———> CaSO4 + H2O + Cl2

Objectives of bleaching

  1. To remove the size material from the garments.
  2. To remove the starch present on the garments.
  3. For soft feeling to wear the garments.
  4. To increase the color fastness and rubbing fastness.
  5. To make white the garments.
  6. To achieve the buyer washing standard.

GARMENT WASHING
The technology which is used to modify the appearance, outlook comfort ability & fashion of the garments is called garment washing.

History
1950 was the beginning of RMG in the Western world. In order to control the level of imported RMG products from developing countries into developed countries, the Multi Fibre Agreement (MFA) was made in 1974. The MFA agreement imposed an export rate 6 percent increase every year from a developing country to a developed country. In the early 1980s Bangladesh started receiving investment in the RMG sector. Some Bangladeshis received free training from the Korean Company Daewoo. After these workers came back to Bangladesh, many of them broke ties with the factory they were working for and started their own factories.

In the 1980s, there were only 50 factories employing only a few thousand people. Currently, there are 4490 manufacturing units. The RMG sector contributes around 76 percent to the total export earnings. In 2007 it earned $9.35 billion. This sector also contributes around 13 percent to the GDP, which was only around 3 percent in 1991. Of the estimated 4.2 million people employed in this sector, about 50 percent of them are women from rural areas. In 2000, the industry consisting of some 3000 factories employed directly more than 1.5 million workers of whom almost 80% were female. USA is the largest importer of Bangladeshi RMG products, followed by Germany, UK, France and other E.U countries.

History of garment washing in the world and Bangladesh
The economy of Bangladesh is largely dependent on agriculture. However, the Ready–Made Garments (RMG) sector has emerged as the biggest earner of foreign currency. The RMG sector has experienced an exponential growth since the 1980s.The sector contributes significantly to the GDP. It also provides employment to around 4.2 million Bangladeshis, mainly women from low income families.

Garments washing
Fig: Garments washing

Requirements of garments washing

  • It should be removed size materials from the garments. Hence feels soft during use.
  • It should be removed any dust, dirt, spot, impurities or germ which is present or added in garments during manufacturing.
  • It should be shrinkage occurred i.e. no possibility of further shrinkage of wash garments due to washing.
  • It should be attracted the customers or buyer by using different types of fashionable washing and market developments.
  • It should be produced similar or different outlook in the garments by different washing techniques.
  • It should be created wash look appearance in the garments. After washing the garments create a new look which seems the new touch of fashion.
  • It should be created color or tinted affect in the garments which also seems the best touch of the garments.
  • It should be created faded affect in the garments.
  • It should be possible to wearing directly the garments after purchasing from the shop.
  • Should be used new/ modern/ latest machines.
  • It should also be produced fading affect in the specific area of the garment as per specific design.
  • It should be comparatively more profitable than others.

Effects of garments washing

  1. Change the appearance of the garments.
  2. Change in size.
  3. Change in color.
  4. Change out look of the garments.
  5. Change in comfort.
  6. Change in design.
  7. Change in fashion, etc.

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TYPES OF WET AND DRY PROCESS

  1. Normal wash / Garments wash/ Rinse wash.
  2. Pigment wash.
  3. Caustic wash.
  4. Silicon wash.
  5. Stone wash.
  6. Enzyme wash.
  7. Stone Enzyme wash.
  8. Acid wash.
  9. Bleach wash.
  10. Tinting & over dyeing.
  11. Sand Blasting.
  12. Hands scraping.
  13. Over all wrinkles.
  14. Permanent wrinkle.
  15. Grinding & Destroy.
  16. Broken & Tagging.
  17. P P Spray & P P Sponging etc.

Machine names which are used in washing plant

  1. Sample washing machine (horizontal/vertical)
  2. Washing machine
  3. Hydro extractor machine
  4. Dryer machine
  5. Chemical mixture machine
  6. Industrial oven
  7. Boiler
  8. Submersible pump
  9. Grinding machine
  10. Tagging machine
  11. Steam chamber for crinkle
  12. E.T.P
  13. Generator
  14. Sand blasting gun
  15. Sand blasting chamber
  16. Spray gun and dummy
  17. Screw compressor

Description of Washing machine, Dryer, Hydro-extractor:

WASHING MACHINE
A washing machine (laundry machine, clothes washer, or laundry) is a machine designed to wash laundry, such as clothing, towels and sheets. The term is mostly applied only to machines that use water as the primary cleaning solution, as opposed to dry cleaning (which uses alternative cleaning fluids, and is performed by specialist businesses) or even ultrasonic cleaners. The definition of washing is “To cleanse, using water or other liquid, usually with soap, detergent, or bleach, by immersing, dipping, rubbing, or scrubbing”. The term machine “A device consisting of fixed and moving parts that modifies mechanical energy and transmits it in a more useful form”.

HISTORY
Laundering by hand involves beating and scrubbing dirty cloth. It is hard work even with manufactured aids like washboards and soap to help.

Clothes washer technology developed as a way to reduce the drudgery of this scrubbing and rubbing process by providing an open basin or sealed container with paddles or fingers to automatically agitate the clothing. The earliest machines were hand-operated. As electricity was not commonly available until at least 1930, some early machines were operated by a low-speed single-cylinder hit and miss gasoline engine. By the mid-1850s steam-driven commercial laundry machinery was on sale in the USA and Great Britain Technological advances in machinery for commercial and institutional laundries proceeded faster than domestic washer design for several decades, especially in the UK. In the US there was more emphasis on developing machines for washing at home, as well as machines for the commercial laundry services which were widely used in the late 19th and early 20th centuries.

Because water often had to be carried, heated on a fire for washing, then poured into the tub, the warm soapy water was precious and would be reused over and over, first to wash the least soiled clothing, then to wash progressively dirtier laundry. While the earliest machines were constructed from wood, later machines made of metal permitted a fire to burn below the washtub, to keep the water warm throughout the day’s washing.

Removal of soap and water from the clothing after washing was originally a separate process. After rinsing, the soaking wet clothing would be formed into a roll and twisted by hand to extract water. To help reduce this labor, the wringer was developed, which uses two rollers under spring tension to squeeze water out of clothing and household linen. Each item would be fed through the wringer separately. The first wringers were hand-operated, but were eventually included as a powered attachment above the washer tub. The wringer would be swung over the wash tub so that extracted wash water would fall back into the tub to be reused for the next wash load.

The modern process of water removal by spinning did not come into use until electric motors were developed. Spinning requires a constant high-speed power source, and was originally done in a separate device known as an extractor. A load of washed clothing would be transferred from the wash tub to the extractor basket, and the water spun out. These early extractors were often dangerous to use since unevenly distributed loads would cause the machine to shake violently. Many efforts have been made to counteract the shaking of unstable loads, first by mounting the spinning basket on a free-floating shock-absorbing frame to absorb minor imbalances, and a bump switch to detect severe movement and stop the machine so that the load can be manually redistributed. Many modern machines are equipped with a sealed ring of liquid that works to counteract any imbalances.

What is now referred to as an automatic washer was at one time referred to as a washer/extractor, which combines the features of these two devices into a single machine, plus the ability to fill and drain water by itself. It is possible to take this a step further, to also merge the automatic washing machine and clothes dryer into a single device, but this is generally uncommon because the drying process tends to use much more energy than using two separate devices; a combined washer/dryer not only must dry the clothing, but also need to dry out the wash chamber itself.

Description of Dryer
The Vincent Vacuo-Dehydrator removes moisture from a continuous flow of material. It is a direct fired dehydration system available in sizes ranging in capacity from 1,000 to 20,000 pounds per hour of water evaporation.

The Vincent Dehydrator is a three pass rotating drum machine with special lifting paddles on the inner and outer surface of each pass. The curtain formed by the material falling from these paddles as the drum rotates assures that all material being fed to the unit receives maximum exposure to the warm gas stream. The drum design and gradually reducing temperatures serve to form an operational balance between declining gas flow energy and declining material moisture content, thereby reducing the chances of burning the product or having it stick to the walls.

Upon leaving the Dehydrator, the material is separated from the air stream in a uniquely designed “low intake” Expansion Chamber. The dried material is drawn through this combination separation and drying chamber under vacuum stream conditions while being cascaded through the hot air stream.

A conventional “high inlet” Cyclone Separator can also be employed. This second devise can be installed in series with the Expansion Chamber when a natural grading of material size is desired.

The Vincent Dehydrator drum is available either in the rotating or stationary outer shell design. The stationary outer design allows the capability of re-cycling partially dried material. Many soupy or sticky materials, which are difficult to dry in most dehydrators, are effectively handled in the Vincent Dehydrator.

When specified with this recycling capability, the Dehydrator allows partially dried material to be mixed with incoming wet material, absorbing excess moisture. In this manner the moisture becomes distributed through a greater number of particles, allowing the mixture to dry easily and quickly. This mode of operation does not reduce the capacity of the Dehydrator.

Operation with the recycling feature is automatic and continuous, yielding high product quality with a minimum of operator attention. Extraction gates allow easy adjustment to compensate for changes in product consistency.

The Dehydrator is fed by a variable speed air lock screw conveyor. This can be easily adjusted through a wide range of speeds to match variations in required evaporation rates.

The Vincent Dehydrator drum is completely assembled and aligned for ease of installation. All parts subject to thermal expansion are provided with expansion joints, resulting in long trouble-free operation. The unit is mounted on a rigid frame, which minimizes the cost of the concrete foundations and which keeps the machine in better alignment. The standard drive arrangement for the Vincent Dehydrator is a heavy-duty gear reducer, mounted on a jack shaft with roller bearing pillow blocks.

All models are of fabricated design and are available in carbon steel, partial stainless and all stainless construction. The drum assembly turns on machined steel tires at either end which are supported by roller bearing turn ions .

PRINCIPLES OF OPERATION
Material enters the Vincent Dehydrator drum at the furnace end through the throat, and removal of water begins immediately. The evaporation of water maintains the product temperature at the dew point condition where the highest efficiency of evaporation occurs.

A temperature monitor at the inlet to the third pass of the drum senses any variation in gas temperature. This correlates to the moisture in the product and automatically adjusts the fuel supply to the furnace. This controls the moisture content of the dried product. Moisture content of plus or minus 1/2% on overall product dryness at pre- determined levels can be attained.

Material is drawn through the concentric drums by the exhaust fan vacuum. As the material dries the density decreases so that it is drawn further through the Dehydrator until only particles of the required moisture content pass out of the drum. The possibility of damage to the product by high temperatures is avoided in the process.

EXPANSION CHAMBER AND CYCLONE SEPARATOR
The Expansion Chamber is fitted to the output end of the Vincent Dehydrator. It is a large tank in which the dried material is separated out of the hot air stream. Material collected in the chamber is then screw fed out of the base through an air lock.

MODEL FOOTPRINT SYSTEM
POWER
REQUIREMENT
HEAT INPUT
‘000 BTU/HR
WATER
EVAPORATION
(LB/HR)
10 5’3″ x 34′ 10 hp 1,760 1,000
25 7’6″ x 48′ 20 hp 4,000 2,500
50 8’6″ x 60′ 37 hp 8,000 5,000
75 9’6″ x 66′ 50 hp 12,000 7,500
100 10’3″ x 70′ 63 hp 15,000 10,000
150 11’6″ x 76′ 84 hp 22,500 15,000
200 13’6″ x 88′ 125 hp 30,000 20,000

Hydro Extractor
Hydro extractor or centrifugal extractor use centrifuge technology for manufacturing laundering which is used in Textile Company. Hydro extracting m/c is mainly centrifuges for generating hydropower. The wet substantial is placed in the hydro extracting machine or centrifugal extracting machine which has a barrier of metal generally steel. The internal drum of centrifugal extracting m/c switches at high speed thus throwing out the water contained in it. The use of this extractor considerably decreases the energy required to dry any material. It is special types of washing machine. Through our technique apartment hard work, exploit new the leading level, and the national patent. This extractor is used after dyeing machine and before tumble dryer machine.

Hydro extractor
Fig: Hydro extractor

Feature of Hydro Extractor:
According the brake way it can be stored: new style liquid pressure starts series and whole converter controlling series.

  • Stainless steel inner roller
  • Anti-erosion, durable using
  • 3-feet suspending holding frame
  • Good for preventing vibration,
  • Safety and reliable
  • Simple operation,
  • Easy maintenance
  • Economic

Specifications of Centrifugal Extractor:

Specifications Name Specifications Value
Product Category Hydro Extractor
Machine Category Centrifugal Extractor Laundry Machine
Product Name Washing hydro extractor for industrial laundering
Product Model According to Manufacturer
Product Class New
Origin Scottish hydro
Brand/Manufacturer Name of Manufacturer
Agent in Bangladesh No/Yes
Power 380v
Temperature Normal
Certification SGS/Others
Production Capacity 500 Set/Sets per Month
Rated capacity 100 Kg
Drum speed 640 rpm
Drum size 1000*400mm
Motor power 7.5kw
Motor Speed 1400(r/m)
Motor Frequency (HZ) 50
Dimension 1670*1460*1000mm
Weight 350kg
Description Hydro power of hydro extracting machine has 3 legs suspended instruction can avoid shock caused by unbalanced loaded

Activities of Centrifuge Extractor for Industrial Laundering
Centrifugal extractor machine is used for removing extra water from fabric by centrifugal method. Normally 75% water is passed away by this technique of hydropower.

Function of chemicals in bleach wash

Anti-staining Agent
A mixture of special macromolecules and surfactants, especially for anti-back staining during desizing and washing in denim rinsing. The basic problem in enzymatic washing of denim is back- staining of detached indigo dyes on fabric surface. Hence, it reduces the contrast effect/fading effect, which garment washer want to produce on denim.

  • FOB Price: US $1.4-1.8 / Kilogram
  • Appearance: pale yellow flow liquid
  • Ion: nonionic
  • Solubility: soluble in cold and hot water…
  • Classification: Chemical Auxiliary Agent

Characteristics and advantage

  1. Has good emulsifying, dispersing and absorbing ability for indigo dyes, can relent indigo back staining and improve color contrast and fabric brilliance.
  2. Can improve color fastness after stone washing.
  3. Be used with enzyme or used general washing process, improve effect of washing.
  4. Be high concentrated, dilute it before using, stable diluted solution, easily used.

Potassium Permanganate:

  • FOB Price: US $1000-2000 / Metric Ton
  • Origin: China

After desizing it is sprayed in garments area, it helps for color out from garment during Enzyme wash. Potassium permanganate (KMnO4 + H3PO4 + H2O) solution applied or stray on the garments so oxidizes the cellulose & color is partially removed according to the intensity & solution.

The process of acid washing jeans used chemicals, stripping off the color of the top layer, leaving the white fabric exposed. The color remained in the lower layers of the material, giving it a faded look. Acid washing could be done overall or made to look splotchy treated with potassium permanganate.

Any time we mess with chemicals such as bleach or chlorine or PP, be sure to protect workers by wearing mask & aprons, so it is best to be fully prepared. Also, protective rubber gloves and safety glasses are highly recommended. These products can burn skin and eyes pretty badly.

  • After PP Spray & PP Sponging need to neutralize the garment per sodium metasulphite, then whitish effect come on respective area of garments.
  • Stock solution is 5% i.e. 40-liter water 200 gm. potassium permanganate & phosphoric acid.
  • PP Spray is done by nozzle and has a switch to start & stop.
  • For Spray on garments need dry air which is supplied from screw compressor and PP stock solution tank.
  • PP Sponging is done manually.
  • By foam / fabric pcs wet in PP stock solution and rubbing particular area of garment by hand as a result fading effects on garments.

Caustic soda (NaOH)
Caustic soda is a deliquescent white crystalline solid, which readily absorbs moisture and carbon dioxide from the atmosphere. It is used for mercerizing cotton.

FOB Price: US $510-520 / Metric Ton

Function of caustic soda

  • Caustic is the strong alkali used in garments washing to introduce an alkaline condition.
  • Caustic created the role in bleach technique without color change the garments.
  • Caustic has a cleaning power which is more powerful than soda Ash.
  • Fading affect/old looking affect come rapidly on garments by the action of caustic soda.

SODA ASH (Na2CO3)
Sodium carbonate is a white crystalline solid containing water of crystallization. It is used in laundry as washing soda. It is also used for softening water.

FOB Price: US $190-195 / Metric Ton

Function of soda ash

  • Soda ash created alkaline medium for the breakdown of pigment dye.
  • It has a cleaning power.
  • It has also help color fading effect of garments.

Detergent
Detergent is used to remove impurities from the Garment fabric surfaces and temperature helps detergent to enhance its action. During coming these impurities, some pigment will be washed out from the pigment dyed or printed area of the garments. As a result, fading affect will be developed.

The simplest way to inactivate any detergents left in the fabric is to neutralize the pH to between 6.5 and 7.5 through addition of a small amount of acetic acid. Through this method, the activity of the alkali and surfactants is eliminated.

For fabrics with a high content of synthetic fibers it may be necessary to add small amounts of cationic surfactants that can neutralize the charges of anionic surfactants and thus prevent static electricity. Using non-ionic or amphoteric surfactants normally makes such additions unnecessary.

Sometimes the fabric softeners also include small amounts of perfume to provide a pleasant scent.

  • FOB Price: US $1-2 / Piece
  • Place of Origin: CN; ZHE; Brand Name

Powder Detergent

  • FOB Price: US $450-1350 / Metric Ton
  • Package: 1kg
  • Type: Detergent in powder form

Liquid detergent

  • FOB Price: US $1-2 / Piece

Super-cleaning fragrant washing powder

  • FOB Price: US $350-700 / Metric Ton
  • Super-cleaning fragrant washing powder this powder contains a super cleaning gene that dissolves easily and is soft on garments…
  • Type: Detergent

Acetic Acid (CH3COOH)
Acetic acid is a colorless and corrosive liquid with pungent smell of its own. It is miscible with water, alcohol and ether in all proportions. Acetic acid is used in garment industry for dyeing purposes.

Acetic acid is a weak organic acid – the key ingredient in vinegar. It is readily degradable and has no adverse effects in the environment except for the use of oxygen for degradation. It is also readily degradable under anaerobic conditions.4

FOB Price: US $800-810 / Ton

Function of acetic acid

  • Acetic Acid is used to neutralize the garment from alkaline condition and to control the pH value in wash bath.
  • Acetic acid is not a fabric softener in principle but is often used for this purpose in professional laundries.4
  • Acetic Acid is used in Enzyme bath
  • Acetic acid has to be stored and handled with care

Sodium Meta Bi-sulfite
Sodium metabisulfite is an inorganic compound composed of sodium, sulfur and oxygen. Its chemical formula is Na2S2O5. It typically comes in a white or yellowish-white crystalline powder. It easily dissolves in water, which leaves that familiar sulfur (rotten egg) smell.

FOB Price: US $300-350 / Metric Ton

Function of sodium Meta bi sulphite

  • Sodium metabisulfite is used as a bleaching agent in pulp and textile manufacture, as well as a reducing agent.
  • Sodium metabisulphite is used in the washing plant to neutralize the garment from potassium permanganate.

Pumic stone

FOB Price: US $0.1-0.5 / Piece

Properties of pumice stone

  • When the impurities amount will be 10% of a pumic stone its density increases to 1 gm./cm3. Then the stone will not float.
  • Alternative of pumic stone: SYNTHETIC STONE
  • Stone wt. /fabric wt. = 0.5 to 3 /1
  • Dia. of stone-1-7 cm
  • Moisture content-less than 5%
  • Surface properties-less than 5% fines
  • Apparent Density-0.5-0.75gm/cm3
  • Abrasion loss-35%
  • Large, hard stones last longer and may be suited for heavy weight fabrics only.
  • Smaller, softer stones would be used for light weight fabrics and more delicate items.

Softener

Function of softener

  • The purpose of adding ‘fabric softeners’ at the end of the washing process is to neutralize the very small amounts of detergents left in the textiles and thus prevent static electricity.
  • Another main function of the softener is creating softer handle over the garments, it is obtained because when softener is applied on the garments then the each and every treads tends to slip over another.
  • Softener is used to make the garments treated textiles is surface feel that is bath sickly and soft and also provides excellent lubricating properties.

FOB Price: US $1-5 / Kilogram;
Name: China mainland11

Bleaching Powder
Color is produced by molecules which contain chromophores and bleach works upon these molecules to achieve the whitening effect. Oxidizing bleach breaks down the molecules with chromophores and makes them incapable of absorbing any visible light, while reducing bleach converts the double-bonded chromophore to single-bonded, thus making them incapable of absorbing visible light. The same principle is behind the bleaching action of sunlight. The high energy photons of light affect the bonds of chromophores, which in turn results in the gradual fading of color.

Bleaching Powder
Fig: Bleaching Powder

FOB Price: US $300-320 / Metric Ton

Bleaching Clothes in Washing Machine
Bleach helps white clothes to retain their original color time and again. Knowing exactly how the bleach works and what are its active ingredients is very useful. When it comes to bleaching clothes white, there are many things that must be considered, first and foremost is the safety. Bleach can cause harm equally to both clothes and your hands. If chlorine bleaches are combined with ammonia and such chemicals, then that can cause extremely harmful and toxic effects. Hence, to avoid side effects of bleach on your hands, you can start doing it in the washing machine.

There are two basic types of bleaches, namely chlorine bleach and non-chlorine bleach and both are equally good. It is important to make sure that the color and type of the fabric that you want to bleach white in washing machine can sustain bleach. It is also important to find out whether the water in which bleaching will be performed is reacting well with the bleach you are using. If you are sure of these two things, then bleaching clothes in the washing machine is very easy.

Hydrogen Peroxide
Hydrogen peroxide creates the prime role in bleach wash technique. In alkaline medium, hydrogen peroxide breaks up and gives some perhydroxhylion, which discolor the colouring materials and as a result fading effect is developed. Hydrogen peroxide is used in scouring, bleaching bath for white/ready for dyeing of gray fabric garments. It is used also neutralized the garment from alkaline condition.

FOB Price: US $400-550 / Ton.

Function of Hydrogen Peroxide
A. Hydrogen peroxide is created in the atmosphere when ultraviolet rays from the sun hit oxygen in the presence of moisture. It is basically the same chemical make up as water but with an extra oxygen atom. Because of this it breaks down quickly and harmlessly into oxygen and water.

B. Hydrogen peroxide has antibacterial and antiviral qualities and is a strong bleach. The most common form is three to six percent hydrogen peroxide solution and this works best in the home as an all-purpose cleaner.

  • Antibacterial
  • Antifungal
  • Kills mold
  • Kills mildew

Silicone Softener

FOB Price: US $2.0-2.2 / Kilogram

While many people rely on their favorite began to see the value in fabric softeners, and an industry was born. Products like these have evolved to meet additional consumer needs, with the addition of fresh scents, dyes and the ability to reduce wrinkles, make ironing easier, and added stain protection.

The typical product contains chemicals and additives to make the fabric soft and static free. Traditionally, the chemicals deposit themselves onto the fabric, but recent formulas use technology that allows the fabric softener to actually penetrate the fabric. This improves the absorption of the fabric, which in the past has been compromised by use of these products. fabric softener to reduce static cling, soften their laundry and make ironing easier, they rarely stop to think about the science behind softening fabric.13 They were first devised in the early 1900s as a way to reduce the stiff, rough feeling of newly dyed cotton fabric. Early “cotton softeners” were developed using water, soap and oil — the oils most often used being corn, olive, and tallow.

EXPERIMENTAL

Washing of the denim
Washing of the denim cause it to fade which result its unique look. There are at least three fundamental reason that indigo dyed denim washes down to produce lighter and more attractive shades during washing.

The outer heavier dyed yarn surface loses dyed through abrasion by stones, enzymes and chemical effect.

Denim washing
Fig: Denim washing

Indigo dye has intrinsic chemical instability to strong oxidizing agent such as chlorine bleach.

Some of the un-dyed fiber in the interior of the yarn migrates to the yarn surface diluting the color of the yarn.

There are two process involved in denim washing:

  1. DRY PROCESS
  2. WET PROCESS

DRY PROCESS
It is called Dry Process because all the processes which are listed below is done in dry condition, in the other says we don’t use any chemical including water in this process.

Following process are carried out in DRY process. Which are listed below:
1. Brushing
2. Hand whisker
3. Grinding

  • Hand Grinding
  • Wheel Grinding

4. Tagging
5. Clipping

WET PROCESS
It is called wet process because in this way we use certain chemicals to obtain a desired result.

Following process are carried out in wet process. Which are listed below:

  • De-sizing
  • Bleaching
  • Neutralization
  • Softening
  • Hydro-extractor
  • Drying

Working Place

  1. HAMS Washing and Dyeing
  2. Bangladesh University Of Textile
  3. Textile Engineering College, Noakhali

Raw Materials used for bleaching
The raw materials for making household bleach are chlorine, caustic soda, and water. The chlorine and caustic soda are produced by putting direct current electricity through a sodium chloride salt solution in a process called electrolysis. Sodium chloride, common table salt, comes from either mines or underground wells. The salt is dissolved in hot water to form a salt solution, which is then treated for impurities before it is reacted in the electrolytic cell.

Machine names which are used in washing plant

  1. Sample washing machine (horizontal/vertical)
  2. Washing machine
  3. Hydro extractor machine
  4. Dryer machine
  5. Chemical mixture machine
  6. Industrial oven
  7. Boiler
  8. Submersible pump
  9. Grinding machine
  10. Tagging machine
  11. Steam chamber for crinkle
  12. E.T.P
  13. Generator
  14. Sand blasting gun
  15. Sand blasting chamber
  16. Spray gun and dummy
  17. Screw compressor

Machines used for testing

Tensile tester
Qualities offers the most competitive line of Tensile Tester range in the industry. Our comprehensive range of Tensile Tester products, along with our extensive range of grips/fixtures, load cells, extensometers, offer the best price/quality ratio models on the market. High quality, accurate and reliable models with reasonable prices. The Q-Series Tensile Testers range is designed for quick and reliable tensile, compression, flexure (bending), shear, peel, fatigue cycling, and constant load tests on metals, composites, alloys, plastics, elastomers, textiles, and finished products.

Tensile tester
Fig: Tensile tester

Crock Meter Series
The Crock Meter Series is designed to test the discoloration extent of dry textile and leather after abrasion.

Yarn Package Durometer
The HPE Digital version of our Yarn Package Durometer has additional advantages. Prisms can be added onto the test stamp, making it easier to measure on spools with different dimensions.

Frazier Differential Pressure Air Permeability Tester
The Low-Pressure Air Permeability Machine was developed by the National Institute of Standards and Technology of measuring the air permeability of textile type materials. and It is the acknowledged standard of the U.S. Government and the U.S. Textile Industry. The second model, High Pressure Air Permeability Machine is produced on the same principle as the Low-Pressure Machine, but designed with a much greater versatility for use through its higher attainable airflow and differential pressure. Both models are extremely accurate and reliable, very easy to operate, and nearly maintenance free.

These machines were originally developed for measuring the air permeability of textile materials and are, in fact, the standard air permeability testing machines in the industry for quality control, research, development, performance and purchase specifications. It was quickly discovered that these machines are equally adaptable for measuring the air permeability with great accuracy and precision of any material that can be fitted to the physical dimensions of the machine. These materials include all fiber products such as paper, felt, nonwoven materials, filter’s and even wire cloth.

Washing condition

1st step: Different concentration
Bleaching powder 5g/l to 15g/l

SL Concentration Temperature Time
1 5g/L 50oc 15 minutes
2 7.5g/L 50oc 15 minutes
3 10g/L 50oc 15 minutes
4 12.5g/L 50oc 15 minutes
5 15g/L 50oc 15 minutes

2nd step: Different temperature

SL Temperature Concentration Time
1 40°c 10g/L 15 minutes
2 45°c 10 g/L 15 minutes
3 50°c 10 g/L 15 minutes
4 55°c 10 g/L 15 minutes
5 60°c 10 g/L 15 minutes

3rd step: Different time

SL Time Concentration Temperature
1 20 10g/L 15oc
2 25 10 g/L 15oc
3 30 10 g/L 15oc
4 35 10 g/L 15oc
5 40 10 g/L 15oc

Recipe for bleach wash

1st step: (desizing)
M: L = 1:10
Add desizing agent=0.6gm/L
Add detergent= 1gm/L
Temp =60oc
Time = 15-25 min
Drop the liquor
Hot wash at 60oc for 5min

2nd step: (bleaching)
M: L= 1:8
Add bleaching powder =10gm/L
Add soda ash = 5gm/L
Temp = 60oc
Time = 12-15min
Drop the liquor
Rinse twice, each three times.

3rd step: (neutralization)
M: L = 1:8
Add sodium sulphite = 3gm/l
Temperature = 40oc
Time = 10-15 min
Drop the liquor
Rinse once

4th step: (softening)
M: L =1:8
Add acetic acid =0.6gm/l
Add softener = 1gm/l
Time =5 min
Drop the liquor
Unload the garments

5th step: (hydro extractor)
Machine R.P.M =700-900
Time =2-5 min

6th step: (drying)
Temperature =60oc to 70oc
Time = 40-50 min for hot wash
10-15 min for cold wash

WORKING PROCEDURE
Normally solid dyed cotton garments are washed with bleaching agent which reduces the color. So, fading effect on garments is produced.

The working procedure are given bellow in step by step—–

Step 01:

  • A lot size of 1.2kg garments (denim) is considered.
  • Load the machine with water at liquor ratio of 1:10
  • Switch is on for running the machine.
  • Add De-sizing agent to the liquor @ 3gm/l
  • Start steam supply to raise the temperature up to 60oc
  • Continue the process for 20 min.
  • Drop the liquor.

Step 02:

  • A lot size of 1.2 kg garments (denim) is considered.
  • Load the machine with water at liquor ratio 1:10
  • Switch is on for running of machine.
  • Add caustic soda to the liquor @ 2%
  • Add Bleaching agent (Hypochlorus) to the liquor @ 5 ml/l
  • Add stabilizer to the liquor @ 2.5 ml/l
  • Add soda ash to the liquor @2%
  • Start steam supply to raise the temperature up to 80oc
  • Continue process for 70 minutes
  • Drop the liquor.

Step 03:

  • A lot size of 1.2kg garments (denim) is considered.
  • Load the machine with water at liquor ratio of 1:9
  • Add sodium hyposulphite@ 3gm/l
  • Switch is on for running of machine.
  • Start steam supply to raise the temperature up to 60oc
  • Continue this process for 5 min
  • Drop the liquor

Step 04:

  • A lot size of 1.2kg garments is considered.
  • Load the machine with water at liquor ratio of 1:5
  • Start machine running.
  • Add acetic acid to the liquor @2ml/l
  • Add softener @1gm/l
  • Start steam supply to raise the temperature up to 60oc
  • Continue this process for 5 min.
  • Drop the liquor.
  • Unload the garments.

Step 05:

  • Hydro extraction the garments to remove wash of excess water from the washed garments.

Step 06:

  • Load the garments
  • Set Temperature 750C to 850C
  • Time @ 35 to 40 minutes for hot dry
  • Time @ 10 minutes for cold dry

Precaution of washing

  1. Measurement of chemical should be taken carefully.
  2. Concentration, time, temperature should be maintained properly for uniform bleach action.
  3. Proper neutralization after bleaching.
  4. Proper making the samples for various concentration, time, temperature.
  5. Proper drying should be maintained.
  6. Wash hands frequently to reduce the risk of exposure to blood borne diseases.
  7. Wear gloves if there is even a possibility you might have contact with another person’s body fluids.
  8. After the removal of gloves or after exposure to blood or other potentially infectious materials, wash hands with antibacterial soap.
  9. Wear gloves once and discard; do not attempt to wash and reuse.
  10. Clothing or supplies contaminated with body fluids should be placed in doubled plastic bags and tied.

Photographs of washed and unwashed sample

washed sample
Fig1: Raw fabric                 Fig2: Sample 01                Fig3: Sample 02
washed sample.2
Fig4: Sample 03                                 Fig5: Sample 04

Result and discussion

Effect of washing on feel of fabric:
The hand feeling of the fabric improves a lot after performing the washing and this improvement has been found in each successive stages of processing. After desizing process the hand feel become soft than the before stage, but the fabric has become softer after the bleaching process. After softening the fabric exhibited the soft test hand feel.

Effect of bleach wash and softening on fabric specification:
It is clear from Table that the desizing, bleaching a softening imparts significant change in the fabric properties. It has been found that, during these specific processing, the value of fabric surface density has been decreased. The Ends per Inch (EPI) and Picks per Inch (PPI) increased in a lower degree. The Shrinkage property has been found decreases, most significantly in warp way. Cotton fabrics are generally subjected to a considerable tension during weaving especially in the warp direction. This stretch was increased in subsequent finishing processes like calendaring and thus the stretch temporarily set in the fabric. The fabric is then in a state of dimensional instability.

BLEACHING STAGES EPI PPI Warp count, Ne Weft count, Ne Shrinkage(%)
Before washing 79 55 10 11
After washing Sample01 77 50 9 10 L=5.5
W=0.5
Sample02 76 53 9 10 L=6.0
W=1.0
Sample03 75 51 9 10 L=6.0
W=1.0

Effect of bleach wash

warp count

When the bleach washing has been performed, the thorough wetting of the denim tends to bring the fabric back to its more stable dimensions which result in the contraction of the yarns. This effect is generally greater in the warp direction compared to the weft. This is known as relaxation shrinkage. EPI (Ends per Inch) and PPI (Picks per Inch) was increased than untreated denim garments due to this relaxation shrinkage.

Effect of bleach wash on fabric GSM:

Bleaching stages GSM
Before washing 379
After washing Sample 01 371
Sample 02 373
Sample 03 376

bleach wash on fabric GSM

Discussion:
It can also be observed seen from Table that, treatment of the denim garments with hypochlorite bleach at 5g/l concentration cause significant decreased the GSM (fabric weight) of the garments, whereas weight loss (GSM decreased) results have previously been obtained with direct and reactive dyed cotton fabric substrate. During weaving cotton fabrics were subjected to considerable tensions, particularly in the warp direction. In subsequent finishing processes such as calendaring this stretch was increased and temporarily set in the fabric. The fabric is then in a state of dimensional instability. Subsequently when the denim garments was thoroughly wetted in bleach washing, it tended to revert its more stable dimensions which results in the contraction of the yarns. This effect is usually greater in the warp direction than in the weft direction. This is known as relaxation shrinkage. Due to relaxation shrinkage, PPI (picks per inch) was increased than untreated denim garments, as a result fabric weight loss is slightly minimized and 10g/l concentration is optimum result for bleach washing. Although decomposition occurred in hypochlorite bleach washing, at the same time relaxation shrinkage happened, and the GSM/fabric weight loss of denim garments were minimized slightly. This was observed that 10g/l concentration exhibits the minimum decrease in the fabric weight as compared with the other concentrations. Thus, 10g/l bleach wash is optimal and this concentration of bleach exhibited the maximum decrease in fabric stiffness; and maximum increase in water absorption, elongation at break and GSM as compared with the other concentrations.

Effect of washing on color shade of denim fabric:

Processing stage Grey scale ratting
Before Wash             5
Sample 01             3
Sample 02           2/3
Sample 03             2

Discussion:
It is obvious from Table that, bleaching has changed the color of the denim significantly. A higher degree of color fading is achieved after the bleaching treatment. After desizing, a slight change in the color is observed compared to the before wash sample but the change in the color is vast after bleaching. The difference in color change is minimum in softening.

Effect of washing on tensile strength of fabric:
The effects of bleaching powder on denim garment washing with different concentrations from 5g/l to 15g/l of KCI bleach for 20 min were investigated. It can be seen from Table that, treatment of denim with bleaching powder at 5g/l concentration cause significant decrease of tensile strength and this decrease was higher at higher bleach concentrations. It is observed that 15g/l concentration exhibited the highest decrease in the loss of tensile strength as compared with the other concentrations. Bleaching powder decomposed cotton under the conditions used. Bleaching powder first attacked on dyed yarn portion, decomposed them slowly and fibers are partly degraded from the yarn chain and step by step penetrated inside fabric. Therefore, the chemical bonds of primary wall (outer layer) are broken by the decomposition of the aqueous solution of hypochlorite bleach. After that it attacked on secondary wall. The result of this reaction is that the primary wall (outer layer) of the cotton fiber is loosened and broken down quicker with the frictional action (mechanical forces) of rotating cylinder of the washing machine. The effect also depends on the conditions of washing.

Bleaching stage Tensile strength(warp) Tensile strength(weft)
Before wash 545 280
 

After wash

Sample 1 455 250
Sample 2 460 260
Sample 3 440 260
Sample 4 445 255

washing on tensile strength of fabric

Effect of washing on stiffness (Bending Length) of denim fabric:
The cotton fibers are loosened by bleaching treatment as the fibrils are degraded and partly detached from the main fiber chain and softness increased. Moreover, the size materials (Starch) are also removed from the warp yarns. As a result, bending length was less and softness was increased. A significant change can be seen after the desizing as this step reduces most of the size materials from the fabric. As the size materials are removed from the warp yarns (as only warp yarns are sized), the reduction in the stiffness is very much significant in the warp way.

Raw fabric:

Direction Face left Face right Back left Back right Average
Warp 3.5 3.5 3 3 3.25
Weft 2.5 2.45 2.85 2.78 2.645

After bleaching:

Sample 01: (conditions: D=15min, B=5min)

Direction Face left Face right Back left Back right Average
Warp 3.1 3.1 2.9 3.05 3.0375
Weft 2.3 2.3 2.8 2.75 2.5375

Sample 02: (condition: conc.12.5g/l,50oc,15min)

Direction Face left Face right Back left Back right Average
Warp 3.2 3.1 2.85 2.75 2.975
Weft 2.2 2.2 2.55 2.6 2.3875

washing on stiffness

Effect of moisture content and moisture regain:

Washing condition Moisture content Moisture regain
Before wash 3.80 4.10
 

After wash

Sample01 5.74 6.09
Sample02 5.79 6.15
Sample03 6.09 6.48

Moisture content is a measure of the level of water in the denim samples. It can be seen from Table that the moisture contents of the bleach treated samples with various concentrations from 5g/l – 15g/l are similar and are the range of 8.3-8.51%, whereas untreated sample was 7.5%. Same holds true for the elongation at break also. Elongation at break of the treated denim garments with various concentrations is similar and the range of elongation 41-48% lengthwise and 21-22% width wise, whereas untreated sample was 24% and 16% respectively.

Conclusion
The bleaching and softening treatment have a great influence on the mechanical and color properties of denim fabric.

The fading effect can be increased by the bleaching but bleaching also reduces the fabric weight, tensile strength and seam strength which might reduce the serviceability of the garments. So, an optimum bleaching action is required to get the required fading effect and softness without compensating some important properties of denim.

Finally, in denim washing our country has a bright future due to wide spread market of denim garments. We need thorough knowledge on denim treatment process and also on the fashion going around the world. And this project will be a guideline for them who are interested in the sector. pioneer in the field of hard washing. And we believe that this project will be a guideline for the washing plants in understanding and doing various treatments.

References:

  1. HAMS washing & dyeing Ltd.
  2. www.wikipedia.Com
  3. Class lectures
  4. Technology of bleaching & mercerizing (v.a.Shenai)( Book)
  5. “How jeans conquered the world”. BBC News. 2012-02-28.
  6. Mogahzy, Y. E. (2009). Engineering Textiles: Integrating the Design and Manufacture of Textile Products (First Edition ed.). Woodhead Publishing Ltd. p. 362. ISBN 978-1-84569-048-9.
  7. In 1789 George Washington toured a Beverly, Massachusetts factory producing machine-woven cotton denim. (Massachusetts Foundation for the Humanities: Mass Moments)
  8. Bellis, Mary. “Levi Strauss – The History of Blue Jeans”. About.com. The New York Times Company. Retrieved 2010-08-04. “Levi Strauss had the canvas made into waist overalls. Miners liked the pants, but complained that they tended to chafe. Levi Strauss substituted a twilled cotton cloth from France called “serge de Nimes.” The fabric later became known as denim and the pants were nicknamed blue jeans.” In INDIA jeans was introduced by famous model Reddeppa. In French of Nimes or De Nimes shortened to Denim
  9. Coe, Nick. “The Essential Raw Denim Breakdown – Our 100th Article!”. RawrDenim.com. Edmonton, Alberta, Canada: RawrDenim.com. Retrieved 2012-03-28. I had read somewhere that a pair of raw denim is like an individualized canvass. Indeed, the fade results and any other visible marks, rips, or tears are specific you and your body. For a dramatic illustration of what we mean, hop over to Takayuki Akachi’sdocumentary on the “Traveling Denim “.
  10. Slater, Sean. “When Should I Wash My Raw Jeans? – A Rough Guide”. RawrDenim.com. Edmonton, Alberta, Canada: RawrDenim.com. Retrieved 2012-03-28. If you’re able to wear your jeans all day, every day then 6 months may be long enough (or perhaps even too long). But if you’re like many folks who have to wear a uniform or dress professionally for 5 days of the week, then you’ll need more time to achieve the same results, maybe 9 months or more.
  11. Coe, Nick. “The Essential Raw Denim Breakdown – Our 100th Article!”. RawrDenim.com. Edmonton, Alberta, Canada: RawrDenim.com. Retrieved 2014-04-09. Raw denim jeans are typically (but not always) produced with 100% cotton and can be sourced from a number of countries. Some folks will argue that a particular country has the “best” cotton (in terms of durability, resulting denim fades, and worn feel) and some of the most popular sources include U.S.A., Zimbabwe, and Japan.
  12. Coe, Nick. “The Essential Raw Denim Breakdown – Our 100th Article!”. RawrDenim.com. Edmonton, Alberta, Canada: RawrDenim.com. Retrieved 2014-04-09. Ever notice how some raw denim feels really thick (and heavy) while others are much thinner (and lighter)? That’s precisely what is referred to as the denim weight – or, technically speaking, how much a yard of raw denim fabric weighs in ounces (Oz.). Putting aside the manufacturing process, the heavier the denim, the more rigid the garment (also due to starching) and more resistant it will be to abrade.
  13. “Denim Dialogues, Vol. II: Making Them Your Own”. Handlebar Magazine. 2011-09-12. Retrieved 2012-12-01.
  14. “Jeansbeetles.com”. Retrieved 2010-08-04.

You may also like:

  1. Process Flow Chart of Denim Manufacturing
  2. Latest Dry Washing Techniques in Denim Garments
  3. Latest Dry Washing Techniques in Denim Garments
  4. Improving Comfort Properties of Denim Fabric through Washing Treatment
  5. Effect of Random Wash on Denim Fabrics by Using Different Techniques
  6. Textile Recycling and Uses of Recycled Denim
  7. Woven and Knitted Denim Manufacturing and Limitations of Woven Denim
  8. Innovation in Spinning Technologies for Denim Wear

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