Crocking - Abrasion and Wear Resistance

Rub and Color Transfer Testing

What would happen if you bought a brand-new car, sat down on the plush red seat and when you got up, had red dye all over your white pants? The color transfer would NOT make you happy, would it? You might be so mad you would turn around and take the car right back! All this can all be prevented by…. performing proper quality control rub testing such as wet or dry “Crocking”.

What is Crocking or a Crocking test?

Crocking is a quality control test that determines the amount of dye, paint, or color matter that transfers from the surface of a colored or printed material to another by rubbing. The crocking test is used to perform wet or dry abrasion, scuff, and mar tests on flat specimens. It was patterned after the standard pressure and rubbing motion of a human finger and forearm to provide reliable and reproducible test results.

Crocking is usually more of a problem with dark and vivid colors. To avoid color transferring from textiles such as fabrics, yarn, carpeting or leather the proper wet or dry crocking test method should be performed. For fabrics, crocking may occur with the presence of excess dye or if it has been improperly dyed. For painting, crocking may occur when the pigment to binder concentration is too high. It can also be used to perform smudge and smear resistance tests on copies from printers or copiers as well.

What is Wet Crocking?

When dyes bleed due to exposure to moisture it is considered Wet crocking. To test for wet crocking, the standard fabric is wet before rubbing against the test fabric. When dyes bleed due to rubbing or exposure to another material it is considered dry crocking.

How is the Crocking Test Performed?

First the material is positioned on the base using the sample holder. Second the16mm diameter acrylic "finger" is wrapped with the standardized abrasive, square or circular crocking cloth which is held in place with a wire spring clip. Then the “finger” attached to the reciprocating load arm moves back and forth (manually or automatically) in a 100mm straight path creating the rubbing action between the printed material and the white test cloths. The reciprocating load arm is weighted to always provide a constant load on the sample and the counter keeps track of completed cycles. After rubbing under controlled pressure by the finger for a specific number of times, the amount of color transferred to the white test cloths is compared to an AATCC color chart and rating between 1 - 5 is established. Grade 5 = no color transfer, Grade 1 = high degree of color transfer.

Crockmeter Kit for Taber Linear Abraser

The attachment is moved back and forth over the specimen surface to create a change in the appearance of the sample. Modifications to how the test is performed include moving a weighted felt pad across a surface or using abrasive paper to mimic the effects of random scratching.

Crocking can be performed by a crockmeter or a Linear Abrasion Tester with a Crocking Test Accessory Kit. The Crockmeter Kit (166g) which includes a crocking finger attachment, wire spring clip and test cloths is used to convert the Taber Linear Abraser or Reciprocating Abraser into a crock meter.

ACT Test Method Descriptions and Established Crocking Criteria

ACT crocking criteria is the industry standard for measuring crocking. For a complete list of test methods see Taber Crockmeter ACT Test Methods. Their guidelines provide acceptable criteria for measuring crocking on different samples.

AATCC 8* The AATCC 8 is a test method of the American Association of Textile Chemists and Colorists (AATCC). This method calls for a standard white cotton fabric that is rubbed against the surface of the test fabric. To test for wet crocking, the standard fabric is wet before rubbing against the test fabric. After rubbing under controlled pressure for a specific number of times, the amount of color transferred to the white test squares is compared to an AATCC color chart and a rating is established.

Grade 5 = no color transfer Grade 1 = high degree of color transfer * For complete technical details about AATCC 8: http://www.aatcc.org

AATCC 116* The AATCC 116 is a test method of the American Association of Textile Chemists and Colorists (AATCC). This test is specifically used for printed fabrics that do not lend themselves to the AATCC 8 method. The test fabric is held at the base of a Rotary Vertical Crock meter and rubbed with a standard cotton white fabric either dry or wet. After rubbing under controlled pressure for a specific number of times, the amount of color transferred to the white test squares is compared to an AATCC color chart and a rating is established.

* For complete technical details about AATCC 116: http://www.aatcc.org

Upholstery - Woven Fabrics AATCC 8	Dry Crocking, Grade 4 minimum Wet Crocking, Grade 3 minimum
Upholstery - Coated Fabrics AATCC 8	Dry Crocking, Grade 4 minimum Wet Crocking, Grade 4 minimum
Direct Glue Wallcoverings AATCC 8	Dry Crocking, Grade 3 minimum Wet Crocking, Grade 3 minimum
Wrapped panels and Upholstered Walls AATCC 8	Dry Crocking, Grade 3 minimum Wet Crocking, Grade 3 minimum
Drapery AATCC 8 (Solids)	Dry Crocking, Grade 3 minimum Wet Crocking, Grade 3 minimum
Drapery AATCC 116 (Prints)	Dry Crocking, Grade 3 minimum Wet Crocking, Grade 3 minimum

When selecting a fabric, a crocking test should be performed for the fabric's suitability of the application. If a fabric fails, the wet or dry crocking test it will also fail in the field. The wet and dry crocking test ensures the fabric selections made will not have dye transfer issues after installation making for a better product and keeping within the established ACT criteria.

For more information see Abrasion and Wear Resistance Testing