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Textile washing color fastness tester Indigo knitted denim fabric experiment
The textile washing color fastness tester is suitable for the washing color fastness performance of various fabrics and textiles.
Shanghai Qianshi Precision Electromechanical Technology Co., Ltd. was established in 2012. It focuses on the research and development, design and production of textile testing instruments, and provides textile testing instruments and services for academic research units and testing institutions. Shanghai Qianshi is one of the most competitive and R&D textile testing instrument manufacturers in China. The R&D team is composed of a group of experienced engineers. We are committed to serving customers wholeheartedly and striving to promote technological innovation in textile testing instruments.
Indigo yarn is usually dyed with vat dyes. This type of dye is insoluble in water and contains carbonyl groups in its molecular structure. When dyeing, it needs to be reduced to a soluble leuco dye in an alkaline medium with insurance powder and dyed with fibers. After oxidation, it becomes an insoluble dye and is fixed in the fiber. The dyeing process goes through four steps: dye reduction and dissolution, leuco dyeing, leuco oxidation, and post-treatment. Knitted denim fabric is a color-woven knitted fabric woven with indigo cotton yarn and pure white cotton yarn. The grey fabric is not treated after being shaped, so the color fastness is poor and it is easy to fade and stain. Therefore, washing becomes an important factor affecting the color fastness of indigo knitted denim fabric.
Sample organization structure:
In order to make the test have universal significance, three commonly used weft knitting organizations were selected, namely large terry, small terry and twill. The relevant parameters of the samples are shown in Table 1. They are all weft knitted products made of indigo yarn, white yarn and spandex yarn. Most of the indigo color is displayed on the front of the fabric, and the back is white. After washing, the color fastness of the fabric surface changes.
The floating color of the colored yarn and the grey fabric is properly treated. The color fastness level of the fabric is significantly improved after the second washing, which can fully meet the requirements for the color fastness level of denim fabric.
Lightness difference change law:
The absolute value of the lightness difference indicates the degree of change in color depth. Negative values indicate that the color deepens, and positive values indicate that the color becomes lighter. From the change of lightness difference after washing the fabric three times, it can be seen that the color of the fabric has become slightly lighter, and the absolute value of the lightness difference has a decreasing trend, indicating that the color fastness of the fabric has gradually improved and stabilized.
Chroma difference change law:
△a* and △b* represent chromaticity, the positive direction of △a* represents red, and the negative direction represents green; the positive direction of △b* represents yellow, and the negative direction represents blue. As shown in Table 2, the chromaticity change amplitude of the three fabrics after washing is significantly reduced, and the chromaticity deviates slightly, but it is still within a certain color tolerance range, and has little effect on the total color difference value.
2024-11-27 11:36
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