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Table of Content
Serial no Content Page no
01 Introduction 03
02 Bleaching 03
03 Item 03
04 Type of bleach with objective 03-05
05 Important factors affecting bleaching 05
06 Bleaching agent 05
07 General Recipe Steps 06
08 Standard Recipe for Bleaching washes 06
09 Types of machine 06
10 Example of denim pants 06-07
11 Bleach Warnings 07
12 Summary 07
13 Conclusion 07
14 Reference 8
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Introduction
Bleach Refers to a number of chemicals which remove color, whiten or disinfect, often
via oxidation.The bleaching process has been known for thousands of years. But the
chemicals currently used for bleaching resulted from the work of several 18th century
scientists. Chlorine is the basis for the most commonly used bleaches, for example, the
solution of sodium hypochlorite, which is so ubiquitous that many people just call it "bleach",
and calcium (bleaching powder). Oxidizing bleaching agents that do not contain chlorine
most often are based on peroxides, such as hydrogen peroxide, sodium per
carbonate and sodium per borate. While most bleaches are oxidizing agents, a fewer number
are reducing agents such as sodium dithionite.
Bleaching
Bleach is a laundry aid that helps remover dirt and stains from clothing. Bleach creates a
chemical reaction with soil that breaks it down and removes it from clothing. Bleach also has
whitening and brightening effect on clothing. There are two different types of
bleach.Bleach is a product that makes it possible for laundry detergents to be more effective
against stains. Bleach oxidizes food and other particles making them easier to remove from
fabric.
Item: denim.
Type of bleach
1. Chlorine bleach (common household bleach or sodium hypochlorite)
2. Oxygen bleach (all fabric bleach)
Chlorine bleach
Usually comes in a liquid form, but can occasionally be found in a powder form. Chlorine
bleach contains sodium hypochlorite diluted with water. This type of bleach is very powerful
and can also disinfect laundry, but isn't safe for some fabric types.
Objectives:
All fabric bleach is considered safe for most clothing.
Chlorine bleach should always be added to the washer water and mixed in well before
adding clothes. Never pour bleach directly onto fabrics. If using bleach for stain
removal, bleach the entire garment to prevent spotting.
When chlorine bleach is used in the wash, it acts as a disinfectant on bacteria and
viruses and generally whitens fabrics. Care must be taken to use it effectively by
adding it at the correct time and temperature to the wash load. Liquid chlorine bleach
has a limited shelf life. If more than six months old, it may have no effect on stains
and should be replaced.
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Test Items before Bleaching
Before you use chlorine bleach on a garment, test the fabric to see how it will react to the
bleach. First, mix one part bleach to two parts warm water. Find an inconspicuous spot on the
garment like an inside seam or pocket of the same fabric. Use a cotton swab dipped in the
solution to dab the fabric. Allow the spot to dry completely before moving forward. If you
see any change in color on the fabric or a transfer of color to the swab, do not use chlorine
bleach on this fabric.
Never Mix Bleaches
Never mix different types of bleach. You can cause a chemical reaction that is harmful to
your clothing and, more importantly, your lungs. This also applies to other cleaning
chemicals like ammonia.
Dilute for Best Results
Chlorine bleach should never be poured directly on clothing. It can cause weakening of fibers
and extensive color removal. Mix 1 cup bleach is in one quart with warm water before adding
it to the wash tub.
Wait to Add the Bleach
To allow the enzymes in the laundry detergents time to do their job of whitening and
brightening, wait about 5 minutes after the wash cycle begins to add your diluted bleach.
Make it Hot, Hot, Hot
Chlorine bleach works most effectively in hot water. It can be used in warm and cold water
but you won't see the results you expect.
Keep It Fresh
Chlorine bleach loses its potency once the bottle is opened. Bleach should be disposed of
after about six months.
Oxygen bleach
Is safe for use on most fabrics and is sometimes known as color-safe bleach or all-fabric
bleach. Even this type of bleach may not be safe for all fabrics.
Objectives
Oxygen bleach is often called All-Fabric Bleach and is usually safe for all fabrics and colors.
It works more slowly than chlorine bleach and may contain sodium per borate or sodium pre-
carbonate.Oxygen Bleach is a popular ingredient in everything from dish soap to carpet
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cleaners to laundry detergent. Oxygen bleach contains hydrogen peroxide and is safe to use
on many more surfaces than chlorine bleach.
Important factors affecting bleaching
Concentration of a chemical
M: L ratio.
Ph of the liquor.
Temperature of a liquor
Time of the treatment.
Bleaching agent
A bleaching agent is a substance that can whiten or decolorize other
substances.Bleaching agents essentially destroy chromospheres (thereby removing the color),
via the oxidation or reduction of these absorbing groups. Thus, bleaches can be classified as
either oxidizing agents or reducing agents.
Figure:chemical room.
Type of Bleaching Agents
There are different types of bleaching agent. These are-
1. Oxidative Bleaching Agents
2. Reductive Bleaching Agents
3. Enzymatic Bleaching Agents
General Recipe Steps
Bleach wash generally involves steps. These are-
Desizing
Stone wash
Bleaching
Neutralization
Softner Application
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Standard Recipe for Bleaching washes:
NaOH 17ml/kg
SOAP (DTC) 2ml/kg
STABILIZER 5ml/kg
H2O2 30ml/kg
Reaction time 25min.
Speed 50-70m/min
Types of machine
There are different kinds of machine. These are-
Pad roll machine
J-box machine
Kier boiler machine
Bleach used machine
Figure: Wash machine.
Example of denim pants
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Figure: Before wash.
Figure: After wash.
Bleach Warnings
Always check for color fastness first, following the instructions on the container,
before using either type of bleach.
Never pour full-strength bleach into a clothes-filled washer.
Add bleach to washer water, mixing well, before adding clothes.
Never mix bleach with ammonia which causes caustic fumes.
Read and follow care instructions and any warnings on the fabric care label regarding
the use of bleach.
Do not uses bleach on silk, acetate, wool, spandex, polypropylene foam, some flame
retardant fabrics or rubber?
Repeated use of chlorine bleach can weaken cellulosic or cotton/ramie/linen fibers.
Repeated use of chlorine bleach can cause yellowing of fabrics.
Summary
A process that is not physically removes color and adds contrast. A 20 yardroll of fabric,
generally 62 inches in width, is put into a 250-pound washing machine along with chemical.
The fabrics arerotated together for a set period of time. The washing time dictates thefinal
color of the fabric- the longer the denim are rotated the white color becomes and one kind of
contrast is achieved. Thedenim is then rinsed, softened and tumble dried.
Conclusion
This assignment is very importance thinks of ours future life. The bleach wash is the most
important of the garments industry. Before the assignments we have do not idea about bleach
wash. We complete the assignment about bleach wash. Finally we achieve some important
information about this matter.