Bleach Wash of Woven Denims: Analysis of before and after Wash Properties (Part-5)

Bleach Wash of Woven Denims: Analysis of before and after Wash Properties (Part-5)
S.M. Bappy Rana
Dept. of Textile Engineering
Bangladesh University of Business & Technology
Cell: +8801781630519

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Hydro-extracting and drying:
After softening 5 minutes hydro-extracting is done .then we dried the samples in gas dryer at 70°c for 20 mins. Then cold drying is for 5 mins to back the apparels in normal position.

3.7 Working process:

Apparel ( Denim leg panel) .8 kg


Hot wash

Cold wash

Bleach washing

Cold wash


Hydro extracting


Bleach washed Apparel

3.8 Testing & its procedure:

3.9 Following tests are done:
  1. Tensile Strength test.
  2. GSM measurement.
  3. Shrinkage Test.
  4. Count measurement.
  5. EPI and PPI measurement.
  6. Shade variation comparison.
3.10 Testing Procedure:

3.11 Tensile Strength test:
Tensile strength test is done by grab test principle. The sample size is 6" ˟ 4".

3.11.1 Apparatus:
  • Heavy fabric.
  • Fabric strength tester.
  • Scissors.
3.11.2 Machine specification:
  • The horizontal tensile Strength Tester
  • Good brand & Co. Ltd.
  • Capacity: 2000lb
3.11.3 Sample:
  • Size – 6inch × 4 inch.
  • No. of sample – 8 ;Warp Way- 4,Weft way- 4
3.11.4 Working procedure:
  1. At first 6 inch × 4 inch fabric was cut out from a leg panel of fabric. The excess amount of fabric was cut because the two jaws will require at least 2inch each to grip the fabric. Thus 4 samples were cut down for testing warp way strength and 4 samples for weft way strength.
  2. Now, the first sample is fixed with the upper jaw J1 and the lower jaw J2.
  3. The m/c is started and observed the dial until the sample is torn out.
  4. When the sample is torn out the m/c is stopped and the reading is taken.
  5. By this way the others’ reading are taken.
3.11.5 Tensile strength test is done by horizontal tensile strength testing machine of Bangladesh University of Textiles (BUTEX).
Horizontal tensile strength testing machine
Figure: Horizontal tensile strength testing machine
3.12 GSM measurement:

3.12.1 Apparatus:
3.12.2 Machine Specification:
Specification of a GSM Round cutter :
  • Area of Specimen: 100 cm²
  • Diameter. Of Specimen: 113 mm.
  • Type of Cut : Standard
  • Blades : Heavy duty Reversible Blades
  • Fine Brass safety Lock
  • Hand Wheel (Handle) : Special Bakelite Handle
  • For repetitive test without fail the cutting pad should be new rubber-foam pad.
3.12.3 Working Procedure of Measuring GSM of a Fabric:
  1. For Measuring GSM, fabric sample is cut by GSM cutter
  2. Now weight is taken by electric balance.
  3. By this way we get the weight in gram per one square meter fabric.
  4. Here GSM of the fabrics by the GSM cutter is obtained by the multiplying the sample weight with 100.
3.12.4 GSM measurement test is done by GSM cutter from Bangladesh University of business and technology (BUBT).
GSM Cutter
Figure: GSM Cutter

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Mazharul Islam Kiron is a textile consultant and researcher on online business promotion. He is working with one European textile machinery company as a country agent. He is also a contributor of Wikipedia.

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