Videotutorial Rub Fastness
Rubbing fastness refers to the resistance of the color of textiles to abrasion or staining to other textiles. As a rule, dark colors achieve lower rubfastness than light colors. Rubbing fastness plays an important role especially when bright materials come into contact with dark textiles and fouling of the bright materials is to be feared.
The assessment is carried out in 5 levels (authenticity numbers), whereby level 5 means a very high rubfastness and level 1 a very low. One distinguishes between dry and wet rub fastness. Environmentally friendly dyeing processes do not always allow satisfactory rubbing fastness. For the testing of the rubbing fastness a Crockmeter is used as a test device. With the Crockmeter, the resistance of the color of textiles and textile floor coverings to abrasion and bleeding against white friction cloth is tested. Both dry and wet rub fastness can be determined with this test method.
The test laboratory should have a sample size of 30x30 cm. During the tests, standard climatic conditions must prevail in the room. The conditioning of the test specimens takes place for at least four hours in the test environment.
The test requires two longitudinal and transverse test specimens and four cotton bleach fabrics which are bleached, plain and non-finish. Two of the friction cloths are dry and two are completely wetted with distilled water (weight gain of + 95-100% must be ensured). Following the test, the friction fabric must first dry before evaluating. Foreign fiber material that could influence the assessment should be removed.
The specimens are evaluated in the viewing chamber under artificial daylight D 65. For assessment, the gray scale is used to assess the staining according to DIN EN ISO 105-A03.
To determine the grade, the scale is held next to the friction fabric. The contrast of the gray and white field of the scale must correspond to that of the inflamed tissue.
For each test report, one grade is given for the dry and one grade for the wet rubbing fabric. The grade 1 corresponds to the strongest bleeding. The grade 5 is awarded if the textile does not bleed on the friction fabric. Generally acceptable for rubbing fastness "dry" is grade 4 and for rubfastness "wet", grade 3-4. The test standards do not define minimum values.
Textiles - Tests for color fastness - Part A03: Gray scale for evaluation of bleeding (ISO 105-A03: 1993); German version EN 20105-A03: 1994 Edition 1994-10