Color fastness to wash is very important for textile test industry.Color fatness to washing means, A specimen of the textile, in contact with one or two specified adjacent fabrics, is mechanically agitated under described conditions of time and temperature in a soap solution, then rinsed and dried. The change in color of the specimen and the staining of the adjacent fabric are assessed with the grey scales.
In personal experience, in case of fastness test color fastness to washing is the first and most important requirements of buyers.There are varieties of testing procedure, because:
1.Washing conditions may vary from one country to another.
2.The methods on the use of dyed goods.
3.To evaluate repeated washing accelerated test methods are used.
The degree of fading and staining of dyed goods for washing depends upon the following factors:
1.Temperature range may be from 40 Degree centigrade to 95 Degree centigrade.
2.The type and amount of detergent added to the washing bath. In many testing procedures a standard detergent is used.
3.The extent of mechanical action which can be varied by changing the agitation speed in a washing machine or by adding steel ball to revolving the bath.
4.The washing liquor to goods ratio is 50:01.
5.The hardness of water.
6.The rinsing, drying, or pressing methods used to restore the sample after the washing test.