Fabric Testing

The different types of test done on fabric are:

1) Colour fastness to washing

2) Colour fastness to perspiration

3) Spirality

4) Shrinkage

5) Colour fastness to rubbing

1) Colour fastness to washing:

Colour fastness to washing is tested using a laundrometer. A sample fabric of l0x4 cm dimension is taken & is stitched together with a multifiber fabric.

It is then kept in the small steel beakers of the laundrometer together with a solution of I gm of sodium perborate & 4% EC in I litre of water. The temperature set is 40 C & the machine is set for a specified time of 45 minutes, the specimen is removed after the specified time period, washed & dried at 60 C. The washed sample & the multifiber fabric are then checked with grey scale & chromatic transference scale to analyze the colour change.

2) Colour fastness the Perspiration:

This method is intended for use in determinacy the fastness of coloured textiles to the effects of perspiration. It is applicable to dyed, printed or otherwise coloured textile fibers, yarns and fabrics of all kinds and to the testing of dyestuffs as applied to textiles.

The colorfastness to perspiration is checked using prespirometer. For this a specimen of   coloured textile 6 x 6  is mixed with a simulated perspiration solution, subjected to a fixed mechanical pressure in contact with a piece of multifiber test fabric, also wet with the simulated perspiration solution and allowed to dry slowly at a slightly elevated temperature for 6 hrs. Then, the specimen is valuated for colour change and staining on the multifiber test fabric with the help of the AATC gray scale for colour change or staining.

3)      Spirality:-

          For checking the spirality there are three methods used:-

          a) Degree-wise method

          b) AATCC method

          c) Side seam method

a)      Degree-wise method:

The fabric specified by the buyer is taken and a course wise line and a wale wise line is marked in it. The degree of angle between the above 2 line are measured using a protractor. Making and measuring is continued for 10 more places for accuracy and is repeated after washing the specified sample fabric. The difference in measurements before and after the washing process is the spirality of the material.

b)      AATCC Method:-

Take 25x25 cm cloth for checking the spirality by using the AATCC method. The formulae for this method is

Spirality - (AC - BD)

                   ( AC-BD

c) Side seam method:

The Spirality using side seam method is checked using the formula.

Spirality = d/lx 100 (diameter/length) x 100

D= diameter of the cloth by the length of the material.

4) Shrinkage:

The shrinkage test is done to know how much the fabric will shrink after washing. For testing, 50cm. outline square is marked on the specified fabric. Machine stitching is given on the 3 edges of the square. Later over locking stitch is given inside to-make a 35cm inner marking, which is followed by a 25cm marking for spirality. To mark the centre leave 5cm from each side. This method is prescribed by ISO. After marking, put the fabric for washing and drying. Once the drying is completed measure the fabric once again to find out the change in dimension and shrinkage occurred.

Another method used for shrinkage testing is the AATCC method (American Association Textile chemist and colorist). In this method a 60cm outer line and a 50cm inner line is made n the specified fabric. Temperature used is 50 C. The mat6rial is then washed in water containing detergent in to ratio 1:4. It is followed by drying and measuring and find out shrinkage and elongation.

5) Colour fastness to Rubbing:

This test is designed to determine the degree of colour that may transfer from the surface of coloured. textiles to other surfaces by rubbing. It is applicable to textiles made from all fibers in the form of yams of fabric whether dyed, printed or otherwise colored.

For testing a coloured test specimen fastened to the base of a crock meter is rubbed with a white crock test cloth under control conditions. Colour transferred to a white test cloth is accessed by comparison with the AATCC chromatic transference scale or gray scale for staining.