Dyeing and Printing

Dyeing And Printing 3(2+1)

Lesson 09 : Color Fastness Tests

Fastness To Perspiration

Perspiration may change the colour of the fabric.

• Perspiration may cause loosening of some dye which may be transferred to other parts of the fabric.

  
  

  Fig of Perspirometre
  

• This loosened dye may cause staining of white or lighter coloured fabrics worn next to the coloured fabrics
• In perspiration test one or all these three things may happen.
1. Colour change of the dyed fabric.
2. Loosening and uneven redeposit ion of colour on coloured fabric.
3. Staining of material next to coloured fabric.

The device used for testing colourfastness to perception is “perception tester” or perspirometre.

• For the perspiration test, a slightly acid solution is used on one piece of coloured cloth or test specimen and a slightly alkaline solution is used on another piece of coloured cloth or test specimen. Both specimens are tested.
• For testing the dyed fabric for fastness to perspiration, two test solutions are prepared one solution is of acidic solution and the other is alkaline solution.
• The dyed fabric is soaked in acid solution such as dilute acidic acid for a period of 10 min. After ten minutes the fabric is squeezed out of solution and wrapped in undyed cloth without rinsing. Permit gradual dyeing and leave the material rolled for a few days.
• Prepare a second similar roll of coloured and white cloth wet with the alkaline perspiration solution. Open up the rolls and compare the two dried samples with the original for change of colour.
• Also the two white clothes are examined for stains. Rate for both of these properties as none, slight, noticeable or pronounced. Give results for both the acid and the alkaline tests.
• Perspirometre is the device used for testing colour fastness to perspiration.