Because the fibers of colored 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 The uniformity of the yarn evenness index is lower than that of natural yarn, while other quality indexes have been improved to varying degrees.
1. Inspection method
1) Based on cheese, each batch 10 blackboards.
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 Check for obvious color knots on the sides of each grid for front and back inspection.
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
Obvious color knots in colored yarn Different from the neps of natural yarns, it is the main indicator that affects the quality of knitting. Therefore, the obvious color knot inspection of colored spun yarns should also be combined with the physical quality of the knitted fabric surface. Usually, color spinning factories will increase the number of fabric samples for inspection.
3. Color fastness and color difference test
Due to the color of color spinning yarn It is the required color of the finished product, so 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.
