During daily use of textiles, friction between different fabrics often occurs due to the movement of human limbs. Especially when people wear clothing with dark and light colors, the friction-resistant color fastness of dark fabrics must be sufficient to prevent repeated wear and tear. Transfer to light colored fabrics after prolonged use.
In order to assess the color fastness to rubbing of textiles, at present, the test method of GB/T 3920-2008 “Color Fastness Test of Textiles – Color Fastness to Rubbing” is generally used. The color fastness of textiles to rubbing is tested. This method determines the color fastness of textiles to rubbing by evaluating the staining degree of standard white cloth. Although the method is simple, practical and popular, the causes of friction staining have been less explored.
This article analyzes the cause of staining from a mechanism through microscopic observation and analysis of the stained area of white cloth and the fiber composition of the sample, thereby hoping to improve the color fastness of textiles to rubbing. Helps.
Test
1.1 Test materials
Samples: This test selected two samples (polyester and lyocell blended fabrics) that were stained after friction tests in daily tests.
Cotton cloth: meets the requirements of GB/T 3920-2008.
Distilled water: meets the requirements of GB/T 3920-2008.
1.2 Test Equipment
Color fastness to rubbing testing machine: maintains constant pressure and complies with the requirements of GB/T3921-2008. CU-2 type fiber microscopic image detection analyzer, with a magnification of 100 times to 500 times. Balance: accuracy is 0.01g.
1.3 Rubbing fastness test steps
According to the provisions of the standard method After preparing the sample, clamp the sample on the friction table, then clamp the standard dry friction cloth and the wet friction cotton cloth with specified moisture content on the friction head respectively, and the pneumatic machine performs reciprocating friction for the specified number of times.
1.4 Microscope observation test steps
Cut out circular stains respectively The cotton cloth samples and sample samples in the colored area were sectioned with a Hastel slicer and then observed and photographed using a microscopic image detection analyzer.
1.5 Test results and analysis
Use circular friction heads respectively The friction test was conducted on the pile and twill fabric samples. The pictures of the stained cotton cloth (the left side is dry friction and the right side is wet friction) are enlarged and shown in Figures 1 and 2. It can be found from the picture that wet friction staining is generally more serious than dry friction staining. In the actual testing process, the vast majority of samples conform to this rule. Analysis of the reasons is mainly related to the following two points:
1) During the wet rubbing process, the dye is more likely to migrate from the sample to the cotton cloth after being moistened (Figure 1 );
2) During the wet friction process, the fiber hairiness on the surface of the sample is easy to fall off after friction, and the fallen fibers are wetted During the reciprocating friction, entanglement is more likely to occur, and then small balls are formed. The small balls fall off and are transferred to the cotton cloth, which objectively increases the staining of the cotton cloth (Figure 2);
When discussing the causes of staining caused by friction, in the past, more tendencies were held that dye transfer occurred. In order to explore this issue, the stained area of the cotton cloth was cut out and observed under microscope magnification, and microscopic images of the stained area were captured (Figure 3 and Figure 4).
From Figure 3, it can be found that there are black smooth rod-like fibers in the stained area of the cotton cloth. Since they are not cotton fibers (no flat ribbon-like twist characteristics), It is foreign foreign fiber. Further analysis can determine that the foreign fiber comes from the sample. From Figure 3, it can also be found that there are black particles (see red circles) in the microscopic image of the stained area. During the microscopic analysis, it was found that the black particles can move on the glass slide. After analysis, it was determined that these were dye particles, also from the sample.
Figure 4 is a microscopic picture of the stained area of cotton cloth (the sample is blue twill fabric). It can be found from Figure 4 that there are some Cotton fibers are blue. Since they are not foreign fibers, they should have been transferred from the sample.The imported blue dye dyed it blue. This shows that dye transfer is also one of the important reasons for friction staining.
Conclusion:
After conducting friction tests and verification on the samples Microscopic analysis of the stained area shows that the color transfer of textiles after friction testing is mainly due to two reasons:
First, the dye has transferred, especially when the sample is wetted Afterwards, the dye is more likely to transfer, which is why the color fastness to wet rubbing is generally worse than the color fastness to dry rubbing. It should be pointed out that the dye has transferred and may dye the fibers on the surface of another sample; it may also be difficult to dye and remain in the form of particles on the surface of another sample.
The second is that the fibers fell off under the action of friction and were transferred from one sample to another.
The poor color fastness to rubbing of textiles may be affected by these two aspects, or it may be dominated by a certain factor, such as dye transfer and dyeing. .
To sum up, to improve the color fastness of textiles to rubbing, we must first focus on improving the color fixation of textile dyeing; in addition, we must improve the surface of textiles. Wash the floating color thoroughly; finally, the hairiness on the yarn surface should be firm and not easy to fall off. </p
