1. Why need to assess the staining after soaping?
The color of clothing is seriously faded during washing, the color of the washing water is very dark, clothing enterprises are relatively passive when encountering such complaints, but when clothing enterprises conduct soaping color fastness tests on clothing with such problems, the conclusion is qualified. Many people will not understand why the test results of clothes with such serious fading will be qualified.
The reason is that the AATCC, ISO, GBT standards for color fastness to soaping only assess the discoloration of the fabric itself and the staining of the standard interlining, without considering the depth of the solution color after washing.
The clothing standard 《FZT 73020-2019 Knitted Casual Clothing》 stipulates that the degree of staining of qualified clothing products is ≥2-3, and the degree of staining of the first-class and superior products is ≥3.
2. What is staining after soaping?
According to GBT3921 standard method A to test the color fastness of soaping, take the residual liquid after soaping, and use GBT251 with the gray card to evaluate the staining degree of the residual liquid after soaping.
3. Assessment method
Liquid configuration: weigh 5g soap slices and dissolve them in 1L of three-level water.
Put the prepared test combination sample into the soap washing cup, add the preheated soap solution to 40±2℃ according to the requirement of 50:1 bath ratio, put the lid on the cup, put the soap washing cup into the soap washing machine, and test at 40℃ for 30min.
At the end of the test, the residual soap removed by filtering impurities was poured into the colorimetric tube (diameter: 25mm). The unwashed soap with the same temperature as the test was taken as the reference sample, under the D65 standard light source, with white cardboard as the background, the staining degree of the lotion was evaluated by gray card, and the grading was completed within 15min.
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