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Friday, August 28, 2015

Different Types of Chemicals used in Garment Washing Plant

Different types of Chemicals are used in the garment washing plant. Some chemicals are used to whiten the fabric; some change the surface tension of water and some fix the dye particles etc.

Chemicals used in Garment Washing

Now we are going to discuss about some common chemicals which we use in the washing plant –

Whitening Agent
Whitening agents increase the whiteness of the garments. After using these agents, the garments become whiter. Basically we use this chemical for white garments to make it whiter. As for example, Optical brightener, 4bk etc. are whitening agents. After applying this agent, the molecules are attached with the garments. When light fall on the garments the molecules will emit the light and garments will show more whiteness and brightness.

Hygroscopic Agent
Hygroscopic agent can be defined as the agent, which can easily absorb water from nature. When the surrounding environment becomes wet then we can use this agent to avoid excessive moisture from the garments. As for example: Calcium chloride, Amylopectin etc.

Wetting Agent
Wetting agent is a chemical which reduces the surface tension of a liquid. Generally, the molecules of a liquid try to bond together and cause surface tension. A wetting agent stretches these bonds and reduces the tendency of the molecules to hold together, which permits the liquid to spread more easily across any solid surface.

Fixing Agent
The agent which is used to fix the dyes with fabric is called fixing agent. This agent is used when we need to set color on the fabric. As a result, colorfastness to wash, colorfastness to light and crocking etc. are improved.

A detergent is a surfactant which has cleaning properties in dilute solution. In most household contexts, the term detergent by itself refers specially to laundry detergent or dish detergent, as opposed to hand soap or other types of cleaning agents. These are commonly available as powder or concentrated solutions. Detergents work like soap because they are partly hydrophilic and partly hydrophobic. Their dual nature facilitates the removal of oil, wax, and grease from the fabric during washing.

Softening Agent
The chemicals which we use to soften the garments are called softening agent. This agent is widely used in the washing sector because it improves the hand feeling of the garments. There are many types of softener but cationic and non ionic softener is mostly used. For color garments, cationic softener is used and for white garments, nonionic softener is used. Softener works inside the garments cellulose.

For final finishing of the garments, silicon is used. It ensures the excellent smoothness, good hand feel and nice durability of the garments. Silicon emulsion imparts ultra smoothness finish and silky hand feel finish. Though silicon is one type of metal, it has high lubricant properties.

Sequestering Agent
This agent is used to dissolve the calcium and magnesium ions present in water. Calcium and Magnesium ions create problems in wet processing causing pin-hole effect. Sequestering agents are also called Chelating agent. The following are the three main stages in which sequestering agents are used:
  • Pretreatment
  • Bleaching
  • Dyeing
Stiffening Agent
This is the chemical that we use to stiff the garments. Resin, Silicate and Melamine etc. are the examples of Stiffening agent.

Waterproofing Agent
The chemicals which we use to protect water absorbency are called water proofing agent like PVC.

Rubbing Fastness Improver
The chemical which improve the rubbing fastness of the garments is called rubbing fastness improver.

Defoaming Agent
A defoamer or anti-foaming agent is a chemical additive that reduces and hinders the foam formation in the liquids during industrial operations. In industrial operations, foams pose serious problems. They produce surface coatings. They prevent the sufficient filling of the containers. A variety of chemical formulas are available to prevent formation of foams.

Enzymes are proteins, composed hundred of amino acid which are produced by living organism. They are responsible for number of reactions and biological activities. It is also biocatalyst and organic compound of higher atomic weight. They are very specific about their work.
Enzymes are used for cleaning product as cleaning and fabric care agent. Most of the enzymes break down soils and stains.

Bleaching Agent
Bleaching agents are chemicals that can remove or lighten color, usually via oxidation or reduction. Bleaching agent is generally used for removing color from garments. It is also used in other industries. There are mainly two types of bleaching agents, one is oxidizing like H2O2 and another is reducing like H2S.

Caustic Soda
Caustic is a strong alkali. It works as a cleaning agent. We use it in the washing bath for removing color and cleaning. It increases the PH value of the liquor. It also works as a desizing agent. Its chemical structure is NaOH.

It is also alkali like substance to remove color. It also increases the PH of the solution. We also use this for desizing, cleaning and scouring. Soda is also known as soda ash. Its chemical structure is Na2CO3.

Acetic acid
It is one kind of acid that has various uses at washing plant. This chemical is used to control PH and also for cleaning. Its chemical structure is CH3COOH.

Stone is specially used in denim garments to get high or low abrasion. We use pumice stone (should be iron free) when we need more abrasion on denim garments. The garment will not pass the metal detector if the iron is stayed with this stone. Stone size is available 2/3 and 3/4. Generally we use ¾.

Rubber Ball
Rubber ball makes the garment softer than soft. We can improve the softness of the garments as well as abrasion by using rubber ball.

Hope that you the readers have learn many things from this article. Please stay with me for more information.

Thursday, August 27, 2015

Difference between Sand Blast and Hand Sand

Sand blast and Hand sand both are dry process. Actually these processes are done at unwashed condition. Dry process is done to ornament the denim garments. Although both the processes are dry, there are many differences among these processes.

Sand Blast
This is the process that also applied for removing the color. This process is done by air flow gun with the help of sand. The high pressure sand is applied on the garments specific area and color will reduce. But this process has some disadvantages, so this process is banned now. This process is done at dry condition of garments

Sand blast effect
Sand Blast Effect
Hand Sand
Hand sand is very important dry process now a day. This process is done at dry condition to remove the color from specific area. In maximum garments we have to do this process because the Sand Blasting process is now banned. This process is done manually with abrasive paper on specific area. At first we have to make the garments and then put on dummy and scrapped. After this process quality is checked and goes for the first wash. The effects will be visible after complete wash.

Hand Sand Effect
Hand Sand Effect
The differences between Sand Blast and Hand and are as follows:

Sand Blast
Hand Sand
This process is done by gun with the help of air flow.
This process is done manually with the help of abrasive paper.
Total indigo is out, so slap is down.
Indigo stay inside, so slap is increased.
Sometimes, metal can be found.
No possibility to found metal.
Effect is on the top of the surface.
Effect is in the depth of the surface.
Less yarn character.
More yarn character.
Process is faster.
Process is lengthy.
Environment is polluted.
Environment is not polluted.
Health hazardous.
Less health hazardous.
Production is high.
Production is low.
Evenness on surface.
Sometimes uneven.
Easy to control.
Difficult to control.
Hope that this article has clarified the differences between the two processes.
You may like also:
Difference between Denim and Jeans

Tuesday, June 16, 2015

What is Napping

Definition of Napping

Napping is chiefly used to obtain a relatively deep hairy surface, but the degree of depth depends upon the technique used. When a fabric is to be napped, the yarns intended for the construction of the cloth are given only a slack twist in the spinning process. The fabric is passed under a roller that has fine steel wires with small hooks on the ends. The hooks scrape the surface of the fabric pulling up fibre ends out of the yarn.

Napped fabric

The fuzzy finish, produced by napping makes a soft fabric, which provides warmth because of the insulative air cells in the nap. The thicker the nap, the more air cells, and the warmer the fabric. In men’s suiting’s, where long wear is desired, a napped surface acts as a protection against objectionable luster. The fact that stains can be removed more readily from a napped surface is an additional advantage. On the other hand, napping may also serve to cover up a sleazy construction and weaving imperfections. It is generally considered that excessive napping tends to weaken the fabric, especially where a heavy nap has been produced, and to increase any propensity to pill.
Single napping signifies that both sides of a cloth have been napped in one direction; double napping signifies that both surfaces have been napped in opposite directions, which produces greater surface density, increased firmness, and greater warmth. Flannelette, wool flannel and duvetyn exemplify napped fabrics. Cotton and spun rayon fabrics are napped when a soft, fuzzy surface is desired.

The Teasel

Vegetable bars called teasels have been used for napping finer grades of wool fabrics. Long cylindrical rollers containing closely set wires, which act like brushes, also perform the teaseling operation. As the brushes slide over the revolving fabric, they pull the top fibres and raise the protruding ends above the surface of the cloth in the form of a fleece like nap. If a heavy nap is desired, teaseling is repeated several times.

Monday, May 18, 2015

What is foam finishing technology | Advantages and Disadvantages

A wet processing technology which uses air in form of dispersion foam for the media of application is called foam finishing.
The process consists of mechanically forming a suitable formulated finish or dye formulation and then applying the foam to textile fabrics. Collapse of the foam distributes the finish on the substrate. The fabric is then subjected to conventional drying and fixing operations. The foam process is currently used in plants for durable press finishing, shrinkage control and softener application to a variety of cotton and polyester cotton blend fabrics.

Foam finishing
It is a high concentration of working solution by adding finishing foam (usually surface active agent) recycling equipment mixed with air to form a certain quality of foam, and then put bubble device to impose uniform foam to the fabric surface of a processing technology.

  • In terms of environmental protection it saves energy by more than 50% and saves chemicals by 10 – 40%, reducing petroleum consumption and cost.
  • Save energy: Low-band fluid volume, low heat less, low use of chemical reagents.
  • Improve production efficiency due to higher speed of fabrics, low liquor content and reduced processes.
  • Improved hand feels of fabrics and enhanced distributions of chemicals.
  • Reduces the loss of fibre strength and improves the product quality.
  • Wet-on-wet technique processing is possible.
  • Foam finishing also enhances product variety. Some noble effects can be produced which is unattainable by normal pad finishing method.
  • Different types of finishing chemicals can be applied simultaneously to both sides of the fabric of high GSM.
  • Reducing environmental pollution has good social and ecological benefits.
  • Can shorten the device length, plant size and reduce investment.
  • High capital equipment cost.
  • Greater care and skill is necessary.
  • Limited range of applicable product.
  • In some cases problem with penetration and levelness.

Monday, April 6, 2015

Application of OBA on Cotton Knitted Fabric in one exhausts method

Optical Brightening Agents (OBA) are colorless or very pale yellow colored organic compounds which when added to a substrate increase the apparent reflectance in the visible by converting ultra-violet radiation into visible light and thus increase the whiteness or brightness.

Application of Optical brightening agent

An OBA can be called a colorless dye which has some substractivity for the fibre on which is to be used.
Optical brightening agents can also be called:
  • Fluorescent brightening agent
  • Physical brightening agent
  • Brighteners
  • White dyes etc.
Fibre and Fabric
Fibre: 100% cotton
Fabric: Plain woven fabric

Here, one of the exhaust methods is used.

Instruments and glass ware
  • Beaker
  • Glass rod
  • Measuring cylinder
  • Bowl
  • Electric balance
  • Scissor
  • Sample dyeing
  • Water shaking bath
  • Tumble dryer
Instruments and materials needed for washing test
  • SDC recommended multi-fibre fabric
  • Water shaking bath
  • Thermometer
  • Dryer
  • Color matching cabinet
  • Sewing machine
  • Grey scale
Reagent required for washing fastness test
  • ISO reference detergent
  • Sodium carbonate
  • Distilled water
  • Pipette
Optical brightening agent: 3%
NaOH: 4gm/l
H2O2: 8gm/l
Wetting agent: 2gm/l
Stabilizer: 1gm/l
Sequestering agent: 1gm/l
Sample weight: 5gm/l
M : L: 1 : 20
Total liquor: 100 cc

Necessary calculation
NaOH Stock solution 4% = (10 X 100 X 100)/(1000 X 4) = 10 CC
H2O2 Stock solution 8% = (8 X 100 X 100)/(1000 X 8) = 10 CC
Wetting agent Stock solution 2% = (2% X 100 X 100)/(1000 X 2) = 10 CC
OBA Stock solution 5% = (5 X 3%)/(5%) = 3 CC
Water required = { 100 – (10 + 10 + 10 + 3)} CC = 67 CC

Process description
  • The dye bath is set at 300C and add sample, wetting agent stabilizer.
  • The temperature is raised at 600C and added NaOH and kept it for 5 minutes.
  • Add H2O2 at 700C for 5 minutes.
  • Raise the temperature 80 – 1000C by 1.50C/min for 60 minutes.
  • Check the shade and cooling down at 500C.
  • Drop down the bath and wash sample at running water and do not squeeze.
Recipe: Acetic Acid 1gm/l

Necessary calculation
Acetic Acid 1% stock solution = (1 X 100 X 100)/(1000 X 1) = 10CC
Water requires = (100 – 10) CC = 90 CC

Neutralization is at 600C temperature for 10 minutes

  • Stock solution should be made carefully.
  • Time and temperature should be maintained carefully.
  • Soda, OBA should be properly dosed.

Wednesday, April 1, 2015

Notes on Water and Wind resistant clothing

Water and Wind resistant clothing

It is seen that the human body temperature can be lost by various methods. Especially in a very cold weather and air-blowing situation, temperature of human body can be lost very quickly. In a cold weather, a person riding bicycle, can loss temperature very quickly. Under these circumstances, the person should cover his entire body by clothing; otherwise his life may be in risk. The design of the clothing should be such that the worm air of the body surface cannot pass through the opening areas of clothing or fabric due to force convection. That means the clothing must be wind resistant.
To manufacture that type of clothing, the fabrics should be of low air permeability property. These types of fabrics are normally very compactly woven or coated or laminated fabrics. In such cases knitted fabrics are not so good because their air permeability is very high. If knitted sweater is used in those situation, should be covered with clothing, made of very compactly woven fabric or laminated fabric.
When clothing worn in cold or wet weather, due to wet air, temperature lost from human body by conduction method rapidly. If in cold and wet weather, air blowing starts, heat loss from human body increases more rapidly. Normally water resistant clothing is also wind resistant. Different types of wind and water resistant cloths are available in the market. Cotton ventile is a water and wind resistant fabric. It is made of very compactly woven cotton fibres, hence becomes more compact, as a result, water molecules cannot pass through the fabric. This type of fabric is used for making raincoat.  
Coated fabrics like polyurethane coated nylon, neoprene coated nylon, or PVC coated polyester fabric could be used for making water and wind resistant cloths. But during sewing the cloths, the needle holes must sealed with water resistant tape, otherwise the performance of the cloth may destroyed by licking water molecules through the needle hole in the seam areas.

Water molecules in vapor form can pass through the cotton ventile fabric, hence during hard work, wearing cotton ventile cloths, possibility of sweating is reduced. But in case of clothing made from coated fabric, sweating will occur as because vapor cannot pass through the coated fabric. Moreover, PVC and neoprene coated fabrics are not damaged by abrasion but polyurethane coated fabric is damaged by abrasion, especially in very cold weather, suitability of polyurethane coated fabric and clothing is very poor.
As a water and wind resistant cloth, Gortex is the latest cloth, which is available in the market. Gortex clothing is made from multilayer fabrics, of which central layer is finished with PTFE coated. The outer and inner layer fabrics are of different construction and weight. The specialty of this cloth is that the central coated layer fabric contains numerous very fine micro holes, which may be up to 109 holes per square inch. These micro holes allows water molecules to pass through in vapor form, hence seating by condensation of water molecules percent in the warm air between body surface and clothing can be avoided. On the other hand, water molecules cannot pass through those micro holes; as a result Gortex is more effective and comfortable as a water and wind resistant clothing.
At the end it should be remembered that, whatever the type of fabric used for making water and wind resistant clothing, the design of the clothing is very important. Because the design of the clothing can reduces the water and wind resistant performance of the clothing.