How to Perform Test for Color Fastness to Rubbing

How to Perform Test for Color Fastness to Rubbing

Select a sample that is a representative of the lot.

Technical Specifications:

Apparatus: For determining the color fastness to rubbing a suitable device ( crock meter) with a rubbing finger, comprising a cylinder of 1.6 cm diameter moving to and from in a straight line along a 10.0 cm track on the specimen with a downward force of 9N should be used.

Rubbing Cotton Cloth: Desized, bleached - without finish and cut into 5cm x 5cm squares, should be used.

Grey Scale- Used to evaluate the stain on the cotton cloth

Preparation of the Specimen

1. If the textile to be tested is a fabric, two pieces, each not less than 14 cm x 5 cm for dry rubbing and two pieces for wet rubbing should be drawn from the sample.

2. One specimen of each pair should have the direction parallel to the yarn yarns and other parallel to the weft or filling yarn.

3. If the textile to be tested is yarn or thread, same should be knitted or woven into fabric to provide 4 specimens each of minimum size of 14 cm x 5 cm, two for dry rubbing and two for wet rubbing. Alternatively 4 specimens should be prepared by forming a layer of parallel strand by wrapping it lengthwise on a rectangular card board of suitable dimension.

4. The test specimen should be fixed on the rubbing device by means of clamps such that the long direction of the specimen follows track of the device.

5.In case of multicoloured textiles, care should be taken to position the specimen in such a way that all colors of the design are rubbed in the test. If the areas of colors are sufficiently large, more test specimens should be taken and individual colours should be assessed separately.

Dry Rubbing

With the dry rubbing cloth flat in place over the end of the finger of the crock meter, same shouldl be rubbed 10 times to and fro in a straight line along a track 10 cm long on the dry specimen in 10 seconds and with a downward force of 9 N.

Wet Rubbing

The above described procedure should be repeated with a fresh dry specimen and with wet rubbing cloth. The wet rubbing cloth should be prepared by soaking a fresh rubbing cloth in distilled water and squeezing the same to contain its own weight of water.

The staining of the rubbing cotton cloth should be assessed with the help of a grey scale.

It is necessary to eliminate dyed fibres pulled out during rubbing and retained on the surface of rubbing cotton cloth, the coloration due to staining by dye stuff only should be considered.

In case of doubt on the assessment of color fastness rating by a single observer, the assessment should be done by at least three observers and overall average rating should be reported.

Report

The numerical rating for dry staining and for wet staining of the rubbing cotton cloth for each direction of manufacture should be reported.