Performance Analysis of Denim Garments by Bleach Wash (Part-5)

Performance Analysis of Denim Garments by Bleach Wash (Part-5)
Authors: Md. Anwarul Haque1
Ariful Hassan
Shantonu Paul Shuvra
Md. ShagorHossain

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

Previous Part

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.
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 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.

Function of softener
  • The purpose of adding ‘fabric softeners’ at the end of the washing process is to neutralise the very small amounts of detergents left in the textiles and thus prevent static electricity.4
  • 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.
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.

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