The common yellowing in textiles mainly includes light yellowing and phenol yellowing. The former refers to the yellowing of the textile surface caused by sunlight or ultraviolet light; the latter refers to the yellowing of the textile surface caused by nitrogen oxides or phenolic compounds. Compared with conventional color fastness
tests such as water resistance and perspiration resistance, the standards and tests for yellowing color fastness of textiles started late. Two textile yellowing test methods: 1. Light yellowing test This unit has conducted certain research on the light yellowing test of textiles. The method used is basically similar to the test method for light fastness of textiles, only the light source used is different. The basic test principle is to cover the head and tail part of a rectangular textile with a shading sheet, and then place it in a special test box. Under a certain temperature and humidity, use a solar lamp or ultraviolet lamp to irradiate the textile for a specified time and observe According to the color change of the lighted part of the sample, the degree of discoloration of the sample is evaluated according to the GB250 gray scale, so as to determine the ability of the textile to resist light yellowing. The test diagram is shown in Figure 1. Figure 1 Schematic diagram of textile light yellowing test 2. Phenol yellowing test According to Caurtauldsmethod and ISO105-X18:2007, the test device for phenol yellowing test is basically the same as the commonly used test equipment for color fastness to perspiration. Wrap the test sample and a piece of fabric used to control the time with test paper containing phenol and sandwich them between glass plates to form a composite sample. After applying a certain pressure, wrap it with polyethylene film and place it in an oven at a specified temperature. , Remove it after a period of time, disassemble the polyethylene film after cooling, take out the control fabric and the sample immediately use the GB251 gray sample card to evaluate the staining grade of the sample. If the staining of the control fabric reaches a predetermined value, the staining level of the sample is the test value, otherwise the test is repeated. The schematic diagram of the test is shown in Figure 2. Figure 2 Schematic diagram of textile phenol yellowing test. Textile yellowing test reference materials[1]ASTMD1148a-2007StandardTestMethodforRubberDeterioration-DiscolorationfromUltraviolet(UV)andHeatExposureofLight-ColoredSurfaces[S]. [2]ISO105-X18: 2007Textiles-Testsfor colourfastness-ofwing Textile yellow color fastness test requirements narrative analysis and discussion. From the above description, the light yellow color fastness of textile mainly refers to the color change of textiles after being irradiated by ultraviolet light or ultraviolet/visible light under a certain relative humidity and temperature environment. This phenomenon is generally equivalent to the light fastness of textiles, but in fact the two concepts are essentially different: the light fastness test mainly refers to the degree of fading of the dyes on the textile after exposure to light; and the light yellowing evaluation It is the yellowing of textiles caused by the addition of bleaching agents and other chemicals in the processing. At present, the standard HG/T3689-2001 'Shoes and Footwear Anti-yellowing Test MethodThe limitations. The phenol yellowing phenomenon of textiles is mainly due to the reaction of phenolic antioxidants (BHF) in the packaging materials with nitrogen oxides (NOX) in the air during the packaging, transportation or storage of textiles, resulting in yellowing or coloring of the textiles change. The Caurtauldsmethod and ISO105-X18:2007 test methods are to simulate the environment of phenolic substances that textiles may be exposed to during packaging, storage and transportation. They have good guiding significance for the assessment of textile phenol yellowing. my country should formulate relevant standards as soon as possible. 4. Conclusion Based on the above analysis, this article summarizes the following suggestions: (1) There are no relevant standards for the yellowing test of textiles at home and abroad, and there are still certain limitations in the testing of reference shoe materials, and it is necessary to conduct research on the formulation of relevant standards . (2) The test of phenol yellowing has been carried out abroad. The release of the ISO standard indicates that this project has attracted the attention of the same industry at home and abroad, and my country urgently needs follow-up in this regard. (3) Compared with the phenol yellowing test, the textile yellowing test is still in its infancy. The future standard formulation and method research should be based on the current shoe material test standards in combination with the textile itself. Features: Carry out detailed analysis and research on the tested temperature, humidity, light time, etc., to more truly reflect the yellowing performance of textiles. Textile yellowing fastness test requirements describe in wool, silk, man-made fibers, leather and other white or light-colored products, bleached textiles all have yellowing to varying degrees. Some occur in the process, and some occur in the process. In the process of use, no matter which one has a serious impact on the appearance quality of the product. However, so far, this type of testing and assessment in China is mainly limited to export products. Due to the lack of standards and methods, most domestic companies do not have relevant assessments. Therefore, it is necessary for textile manufacturers to pay attention to the yellowing fastness test of textiles. And pay attention to better improve the overall quality of products.
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