BLEACHING WASH OF DENIM PANTS

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 bl

BLEACHING WASH

Author- Younus Miraj Shanto-Mariam University of Creative & Technology

UTTARA-DHAKA

Table of Content

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

05 Important factors affecting bleaching 05

08 Standard Recipe for Bleaching washes 06

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

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 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

Standard Recipe for Bleaching washes:

NaOH 17ml/kg

SOAP (DTC) 2ml/kg

STABILIZER 5ml/kg

H2O2 30ml/kg

Reaction time 25min

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

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 yard roll of fabric, generally 62 inches in width, is put into a 250-pound washing machine along with chemical The fabrics are rotated together for a set period of time The washing time dictates the final color of the fabric- the longer the denim are rotated the white color becomes and one kind of contrast is achieved The denim 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

Reference

• http://housekeeping.about.com/od/laundry/g/def_bleach.htm

• http://laundry.about.com/od/laundrybasics/a/howtobleach.htm

• http://www.answers.com/topic/bleach

• http://textilelearner.blogspot.com/2011/03/textile-bleaching-process_5937.html