Because the fibers of color-spun yarn are dyed, some fiber indexes are lower than natural fibers. Especially for varieties with a proportion of colored cotton exceeding 50%, the breaking strength of single yarn and the uniformity of single yarn uniformity index are both lower than Natural yarn, while other quality indexes have been improved to varying degrees.
1. Inspection method
1) Based on cheese, take 10 blackboards from each batch.
2) Requirements for inspection sites: Try to use north-facing natural light sources. During normal inspection, there must be larger windows and no obstructions in the windows to ensure that there is enough light in the windows.
3) Requirements for light source inspection: Usually, the illumination is not less than 400LX (greater than 800LX). When the illumination is less than 400LX, additional light inspection (cyan or white fluorescent tube) should be used. Light should enter from the rear left, the installation angle of the inspection surface should be 45±5° with the horizontal plane, and the shadow of the inspector should not be cast on the blackboard.
4) Inspection steps: First insert the light blue (or other color) base plate between the sample and the black plate, and then press the original black plate on the sample to check each grid before and after Check for obvious color knots on the sides.
5) Note: Do not turn the yarn over during inspection, and the line of sight must be perpendicular to the yarn. Distance is based on the principle of effortless visual effort by the inspector to detect defects.
2. Requirements for color knot inspection
The obvious color knots of colored spun yarn are different from the neps of natural yarns , it is the main indicator that affects the quality of knitting, so the inspection of obvious color knots in colored spinning should also be combined with the physical quality of the surface of the knitted fabric. Usually, color spinning factories will increase the number of fabric samples for inspection.
3. Color fastness and color difference test
Since the color of colored yarn is the required color of the finished product, Color fastness testing is an essential and important item. Specific inspection items include: washing resistance, sweat resistance, abrasion resistance, sunlight exposure, color fastness, color difference, etc., according to GB/T3921-3, GB/T3922, GB/T3920, GB250 and other standards are implemented.
