How to Test pH of Textile material

Testing of pH by water extraction method

Purpose of the test

The pH of the processed textiles must be neutral and within the prescribed limits for a particular end use. The textiles with higher pH value may exhibit yellowing tendencies ,create change of shade upon storage and during shipment, result into poor dye pick up , patchy dyeing and poor colorfastness. very high and very low pH results into degradation of textiles during storage and use , may result into poor softness and harsh feel. pH of apparel fabrics which are in direct contact with the skin or used for baby wear, must be controlled not to make the skin itchy. 

The pH control is very important for in process quality as well as quality of the finished material.

Test method

Boil 250 ml distilled water or deionized water for 10 minutes and put 10+/- 0.1 gm of test specimen in it boil for another 10 minutes. Allow it cool down to room temperature , remove the specimen and squeeze back the excess water in the beaker. 

Test the pH by using a calibrated pH meter within an accuracy of +/-0.1 on pH scale.

The pH of water extract must be tested after prior to dyeing if you are getting uneven dyeing and to be tested after completion of dyeing and soaping to avoid any problems in finishing such as softening and dye fixing etc.  

This information is generalized for day to day in house process control, for detailed information please follow AATCC 81-2006

and ISO-3071. 
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