What is color fastness to washing? The color fastness to washing is the resistance of a material to change in its color characteristics when is subjected to washing.
1.Overview
The washing fastness of textiles refers to the ability of the textile to maintain the original color under the washing condition, that is, the ability of not fading and changing color. ISO 105C01-C05 provides several test methods for color fastness to washing, covering the range from mild to the intense washing operation, as a classic color fastness test method, which is still widely used today. The determination of color fastness to washing of the whole cotton fabric using washing fastness test ISO 105-c03 method, China’s GB/T 3921. 3-1997 standard is based on the modification of the formulation, so its technical content and international standards are not different, applicable to any form of textiles.
In addition to the above 2 standards, there are many international standards on the testing of color fastness to water, such as AATCC 61-1A of US, British BS 1006-C01, ISO 105-c06 of the ISO, JIS L0844 of Japan, etc.
2. Comparison of washing fastness test methods
There are many color fastness to washing standards. Different standards are in accordance with different test methods. We just name four examples as flow.
A. Chinese Standard (GB/T 3921.3-1997)
Take a 4cmx10cm specimen, the front is contacted with a 4~10cm adjacent fabric, stitched along a short edge to form a composite specimen and placed in a stainless steel container with a capacity (550±50) ml [diameter (75±5) ml, high (125±10) ML], injected required amount of soap liquid preheated to (60 ±2) ℃, bath ratio of 50:1. The combination specimen is treated with 30min under the condition of (60±2) ℃, then the combination specimen is removed and washed 2 times with the cold three water, then the 10min is rinsed in the flowing cold water. Squeeze the moisture and expand the composite specimen so that the specimen and the adjacent fabric are only connected by a single seam and are suspended in the air not exceeding 60 ℃. Take out the dry combination specimen and use the Grey sample card to evaluate the discoloration of the sample and the staining of the adjacent fabric.
B. Standards of the American Association of Textile Chemists and Colorants (AATCC 61a-2003, color fastness to washing aatcc)
AATCC test method 61-2013 is another standard which is based on the modification of the formulation. A 50mmx100mm specimen is taken, the front is contacted with a 5mmx100mm adjacent fabric, stitched along a short edge to form a composite specimen and placed in a stainless steel container with a capacity (550±50) ml [diameter (75±5) ml, high (125±10) ml], with injection of required amount of soap liquid preheated to (40±2) ℃, so that the bath 200mL. The composite specimen is processed under (40±2) ℃ for 45min and then removed combined sample, rinsing 3 times with (40±3) ℃ distilled water for 1min, then squeezing away moisture. The combination specimen is expanded so that the specimen and the adjacent fabric are only connected by a single seam and are suspended in the air not exceeding 71 ℃.Take out the dry combination specimen and use the Grey sample card to evaluate the discoloration of the sample and the staining of the adjacent fabric.
C. Japanese industrial standard (JIS l0844-2005)
A 4cmx10cm specimen is taken, the front is contacted with a 4cmx5cm nylon adjacent fabric, stitched along a short edge to form a composite specimen and placed in a stainless steel container capacity (550±50) ml [diameter (75±5) ml, high (125±10) ML], injected required amount of soap liquid preheated to (50 ±2) ℃, bath ratio of 50:1. The combination specimen is treated with 30min under the condition of (50±2) ℃, then the combination specimen is removed and washed 2 times with the cold three water, then is rinsed in the flowing cold water for the 10min. Squeeze the moisture and expand the composite specimen so that the specimen and the adjacent fabric are only connected by a single seam and are suspended in the air not exceeding 60 ℃. Take out the dry combination specimen and use the Grey sample card to evaluate the discoloration of the sample and the staining of the adjacent fabric.
D. ISO Standards (colour fastness to washing ISO 105-C06)
The main differences between countries ‘ methods of measurement are shown in table 1.
3. Experimental Comparison and analysis
Pure cotton samples of black, navy, red, brown, yellow and other colors are tested according to different testing methods, and the colour fastness to washing test results found that there is a certain difference in the fastness of washing values, in which colour fastness to water measured according to the United States and Japan standard is significantly higher than the Chinese standard, the maximum difference of 1 levels, and washing fastness measured based on the Japanese standard slightly higher than the United States standard’s. The difference of washing fastness value is caused by the different conditions of washing temperature and washing time in the color fastness to washing standard of the test specimen.
The solution of dye is related to the water solubility of the fuel molecule. The sulfonic acid in the fuel is bonded with the fiber. When the dyed fabric invades the water, the hydrogen bonding is cut, some dyes will leave the fiber and dissolve in water. The dyed matter in the washing fastness machine is stirred and the pigment of the insoluble dye is also removed from the fiber by agitation.
The higher the washing temperature, the longer the time, the bigger the bath ratio, the more intense the stirring, the higher the dye shedding rate. Chinese and Japanese standards used in the same washing time, bath ratio are the same, China’s standard use of washing temperatureis higher than Japanese standard, and the colour fastness to washing grading is lower to 0.5~1 grade than Japanese standar’s. The United States standard washing temperature is the lowest, but by adding long washing time, increasing the washing bath ratio or adding stirring matters, these ways will increase the dye on the fabric shedding rate.
4. Error analysis
The differences in the adjacent fabric will result in test errors. Though with the same sample and the same method, the results vary when using different adjacent fabrics for stained-color testing. Because of the different fabric structure, composition, yarn branch, density and finishing process, technologies, etc., it will directly lead to the difference of the color-stained property of the fiber fabric, and ultimately affect the color fastness to washing test
When rating the color fastness test sample in the standard light box, the intensity of light will cause the eyes to fatigue if the rating time is too long, affecting the accuracy of evaluation.
When grading, the light source illumination and the specimen surface assumes 40 degrees angle, and the line of sight should be perpendicular to the specimen surface, the distance to 30~40cm advisable, otherwise will affect the evaluation result.
The removal of the loose fibers attached to the surface of the adjacent fabric also affects the evaluation results.
5. Summary
There is a big difference between the values of washing fastness measured by different national test standards, and the test requirements for the fastness to washing of textiles in accordance with Chinese standards are stricter than those of the United States and Japan.
ISO 105-C06 PDF
AATCC standards PDF
AATCC 61 PDF
Colour fastness to washing PDF
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