Category: Wet Processing

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Recommendation for Efficient Enzyme Desizing

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What is enzymatic desizing and what is the recommendation for efficient enzyme desizing

Desizing is the process of removing the size material from the warp yarns after the textile fabric is woven.

Enzymatic desizing is a traditional desizing procedure of degrading starch size on cotton fabrics using enzymes. Enzymes are multipart organic, soluble bio-catalysts, created by living organisms that catalyze chemical effect in a biological process. Enzymes are quite specific in their act on a particular material. A small amount of enzyme is able to decompose a large quantity of the material.

Recommendation for Efficient Enzyme Desizing

(Ref: BTRA – Bombay Textile Research Association)

  • Before enzyme de sizing cloth should be wetted with warm water.
  • Enzyme activity should be tested before use.
  • pH should be controlled.
  • Avoid copper made machines.
  • Enzyme treated cloth keep in a rider room.
  • Treated cloth wash with hot water.
  • Should be careful that enzyme above 70 degrees the centigrade temperature will be inactivated or damage.
Recommendation for Efficient Enzyme Desizing

Recommendation for Efficient Enzyme Desizing

How Enzyme activity Depends on Concentrate pH and Temperature

  • The activity of enzyme increases with the increase of temp but up to certain limit then above that limitation activity decrease.
  • Enzyme stability decrease with the increase in temperature.
  • Enzyme activity decrease with longer time.
  • Changing of pH rapidly changes enzyme activity and stability.
  • If the concentration of enzyme increases then activity decrease.

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Engineer Sheikh Nurja

B.Sc engineer of textile

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Rot steeping Acid Steeping Enzyme Steeping

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Ideas of Rot Steeping Acid Steeping Enzyme Steeping

Steeping is the soaking in liquid (usually water) of a solid so as to extract flavors or to soften it. Some teas are prepared for drinking by steeping the leaves in heated water to release the flavor and nutrients.

Rot steeping

Rot steeping is the oldest & cheapest way of desizing where no special chemical is used. In rot steeping cloth is passed through warm water of forty degrees for this cloth is squeezed up to 100% expression. Although this method is the cheapest but the main disadvantage of this process is it is very much time consuming because it cannot be said that with allocated time sizing material will remove.

Rot steeping acid steeping enzyme steeping Rot Steeping

Acid steeping

Acid steeping is one of the most useful desizing processes where dilute Sulphuric acid is used to Hydrolyze or soften starch. By this method, almost all the starch present in the fabric can be liquefied. Fabrics are impregnated with an acid solution in a room where the temperature is 30 degree and have to keep it for eight to twelve hours for acid steeping. Remember that during storage of fabric in the tempered room fabric should not be dried otherwise it may damage the fabric.

Enzyme Steeping

The safest method of desizing is enzyme steeping. There is no problem of hydrocellulose which ensure good desizing. This process occupies less space but it is more costly than other desizing methods.

The difference among Rot Steeping, Acid Steeping, and Enzyme Steeping

Rot steeping

Acid steeping

Enzyme steeping
De-sizing agent warm water De-sizing agent more dilutes mineral acid De-sizing agent Enzyme
Time 24 hours Time 8-12hours Time 3-4 hour per minute
Hydro-cellulose may from Hydro-cellulose may form No problem of hydro-cellulose
Less wt loss More wt loss Less wt loss
De-sizing process is good De-sizing is better De-sizing is good
More space is required Less space is required Less space is required
Less cost process More cost process More cost process

Written by

Engineer Sheikh Nurja

B.Sc engineer of textile

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Classification and Objects of Scouring

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Classification and Objects of Scouring

Scouring

Desized textile materials till containing oil, fats, and waxes which are removed by alkali or detergent are called scouring.

Classification and Objects of ScouringObjectives of Scouring

  1. To remove natural and added oils, fat and wax are from the textile materials.
  2. Improve hydrophilicity.
  3. Improve absorbency.
  4. Prepare for the next process.
  5. To get uniform bleaching result.

Flow Chart of Scouring

Flow chart of scouring

Flow Chart of Scouring

Scouring Process

There are two types of scouring process-

  • Hand Scouring
  • Machine Scouring

Hand Scouring

In this process, the fabric is boiled in an open trough with NaOH common soda and t.r oil for after a few hours. But be careful so that fabric does not come in contact with air otherwise fabric strength can be reduced. After that wash with cold water sour with dilute HCl to remove alkali from the fabric.

Machine Scouring

Now a day’s various types of machines are available for scouring with alkali. This alkali treatment can be divided into three categories.

  • Lime acid soda process.
  • Caustic soda process.
  • Soap soda process.

Written by

Engineer Sheikh Nurja

B.Sc engineer of textile

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Enzyme Desizing

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Enzyme Desizing

Enzymatic desizing is a traditional desizing procedure of degrading starch size on cotton fabrics using enzymes. Enzymes are multipart organic, soluble bio-catalysts, created by living organisms that catalyze chemical effect in a biological process. Enzymes are quite specific in their act on a particular material. A small amount of enzyme is able to decompose a large quantity of the material.

enzyme desizing

Why Enzyme Desizing is Popular?

  • No hydro-cellulose is formed, fabric strength remain changed.
  • The process is continuous and speedy.
  • The desizing capacity is more.
  • Less floor space is required.
  • Weight loss of fabric is less.

Continuous Enzyme Desizing Process

Normally when malt extract is used as the designing agent it takes about 3-4 hours for complete desizing to occur, but when stronger solutions of the extract are used to reduce the time within 5 minutes.

continuous enzyme desizing process

Continuous Enzyme Desizing Process

In this case, the impregnated fabric has to put in the required pit the length of the floor of the pit should be equal to delivered impregnated cloth in 5 minutes, so enzyme impregnated cloth, pit and washing machine should be synchronized with each other.

Written by

Engineer Sheikh Nurja

B.Sc engineer of textile

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Classification of Desizing

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Classification of Desizing

Desizing

Desizing is the first chemical process in the wet process. Desizing is the term usually restricted to the process of removal of starch (of the size) from the cloth. De-sizing processes can be controlled by desizing process can be controlled by desizing liquor shorter time process. There are several methods for desizing and these can be classified as follows-

classification of desizing

Classification of Desizing

Objectives of Desizing

From the definition of desizing you know that it is a chemical process in wet processing. For this importance, there are several objectives of desizing that can be identified. These are:

  1. To remove starch from fabric desizing is done.
  2. To improve the absorbing capacity of the fabric.
  3. To make ready for the next process scouring, bleaching, etc.
  4. To improve absorbing attain of chemicals.
  5. Increase the luster of dyeing and printing.

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Engineer Sheikh Nurja

B.Sc engineer of textile

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Gas Singeing

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Description of Gas Singeing

As I mentioned earlier to write about gas singeing today I am going to discuss Gas singeing method and also going to share a comparison study of Plate singeing, Roller singeing and gas singeing. Basically Singeing process is done by continuous burning and passing fabric over the flame, where the flame is produced by a combination of air and gas.

Gas Singeing Machine

This machine consists of one or more burners giving a continuous flat or vertical flames, produced by a mixture of compressed air and gas. When fabric passes over the flame and singeing is done as required.

gas singeing

Gas Singeing Process

There are various types of machines depending on burns design. The speed of machines 72-90 m/min depending on cloth varieties. The machines are attached with the water tank to save the fabric from any damage. Now a day’s various improved have been done in the machine design. Improper singeing may be lead to as much as 75% tensile strength loss in the warp directions.

Why gas singeing method is popular than other methods?

  1. Better singeing and projecting fibers of interstices is burned by the processes.
  2. Uniform singeing can be maintained.
  3. Smoothness and evenness of the fabric are increased.
  4. Groove is produced in other singeing machines but gas singeing machines are saving from that problem.
  5. Gas flame can be changed according to fabric with.
  6. Production is height than other machines.
  7. Both sides of the fabric can be singeing.

Due to the above facilities this gas machine more popular than other machines.

The difference among Plate singeing, Roller singeing and Gas singeing

Plate singeing

 Roller singeing Gas singeing
Inter stitches fibers not burned. Same as a plate. Inter stitches fibers burn out.
Due to mental plate friction surface become smooth and luster. Same as plate singeing. Extra luster is not produced.
Fabric moves plate stationery. Both move in the opposite direction. Fabric moves only.
Even temperature maintaining is a problem. Better than plate singeing. Burning is used.
The metal plate is used. The metal roller is used. The gas flame is used.
Speed:150-250 yards/min. Less than plate singeing. Speed250-400 yards/min.
One side is signed. One side is signed. Both sides are signed.

Written by

Engineer Sheikh Nurja

B.Sc engineer of textile

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