The impact of bleaching, dyeing and printing on yarn requirements and organizational structure

The purpose of subsequent dyeing and finishing of woven fabrics is different, and the yarn requirements are also different. Bleached blanks, printed blanks, and dyed blanks all have different yarn requirements, especially cotton-containing woven fabrics. Gray fabrics must be selected according to processing requirements. The organizational structure also has specific requirements for yarn raw materials, which also affects the dyeing and finishing effect. In this article, editor Ran shares the requirements for yarn and the impact of bleaching, dyeing and printing of woven fabrics on yarn and organizational structure.

The bleaching, dyeing and printing of woven fabrics have different requirements for yarns.

(1) Bleached gray cloth: After the gray cloth is bleached, the surface of the cloth will be clear and white, so the defects remaining on the cloth surface are more likely to appear, especially some oil and colored defects (such as slubs, oily yarn, oily yarn, Special attention must be paid to colored yarn, coal gray yarn, “three silks” and heterosexual fibers, etc. Chemical fiber blended and pure textile products have higher whiteness, so they have higher requirements for the above-mentioned defects.

(2) Dyeing blanks: Dyeing blanks are divided into two categories: light-colored blanks and dark-colored blanks. Because of its lighter color, light-colored blanks have higher requirements for oil stains on the cloth surface, yarn defects such as colored yarns, oil yarns, coal ash yarns, “three yarns” and foreign fibers; dark-colored blanks are dyed darker and require higher stains on colored yarns, oil yarns, etc. Yarn defects such as yarn, soot yarn and uneven evenness are highly concealed, but requirements for yarn defects such as snakeskin silk, neps and dead cotton are higher. The problem of white stars in dark blanks is a particularly prominent quality issue. It is mainly caused by low-maturity fibers such as raw cotton middle flaps, soft seed surfaces, dead fibers, etc. that cause the dye to fail to color. You must pay attention to it. Variegated blanks, or medium-light colored blanks, are similar to bleached blanks. They have higher requirements for oil defects and color defects, and have slightly higher requirements for general yarn defects such as slivers and sparse crossbars than dark-colored blanks. Different colors of gray fabrics will have different visual effects on the gray fabrics. According to experience, Shilin colors, snow cyan, beige, etc. are very sensitive to the appearance of streaks in gray fabrics.

(3) Printing blanks: Printing blanks are roughly divided into two categories: dyed background printing and white background printing. Due to the color pattern printed on the cloth, dyeing printing can cover up general oil stains, colored yarns, oily yarns, soot yarns, uneven yarns and other yarn defects and some weaving defects on the surface of the gray cloth; white background Due to the relatively large whiteness on the fabric surface, printing requires stricter requirements for the above-mentioned yarn defects, and sometimes the requirements are even equivalent to those of bleached blanks.

The dyeing and finishing process of woven fabrics is affected by the structure of the gray fabric and the quality of the yarn.

(1) Plain weave: The plain weave has a tight structure and a smooth surface. The coverage probability of warp and weft yarns is basically the same, and the tightness is not much different. Yarn slubs, neps, thick diameters, and wrong wefts in gray fabrics all have very obvious reflections on the dyeing and finishing products. Since generally one bobbin in the spinning department will be concentrated on a section of width, it is very sensitive to the quality of the gray fabric and the weft yarn requirements.Please pay more attention to it. For dyeing and finishing products with higher quality requirements, the warp and weft yarns should be mixed with cotton separately, and care should be taken in terms of raw materials and technology, especially for poplin fabrics with high warp density and low weft density.

(2) Twill weave: The surface of the twill weave has diagonal lines formed by continuous connection of floating points or weft floating points. The intersection points of warp and weft of this kind of weave are less than that of plain weave. Therefore, its weaving density is generally higher than that of plain weave, the fabric tightness is greater than that of plain weave, and the warp density is generally higher than the weft density. The fabric weaves include two up and two down, or three up and one down. The front and back of the two upper and lower cloths are symmetrical, and the warp and weft yarns are basically the same. Three up and one down will expose more warp yarns on the front of the fabric, and warp appearance defects will be easily exposed on the fabric surface. The weft yarn can be concealed because it shows less. For this reason, when considering dyeing and finishing products, we must focus on the quality of gray fabric warp yarns. Defects in twill fabrics are caused by fabric weave errors caused by missing weft threads (equivalent to the thin weft of plain weave fabrics). There are three types of twill fabrics: khaki, gabardine, and twill. Among them, the fabric tightness of khaki is greater than that of gabardine, and khaki is greater than that of gabardine. Generally, the greater the tightness, the more difficult it is to weave, and weaving defects are more likely to occur.

(3) Satin weave: Satin weave has a longer interweaving point spacing and fewer interweaving points, so the weaving density can be higher. The surface of the fabric is smooth and shiny, soft to the touch, and it has a dazzling luster after being dyed, finished, resin-finished and electro-calendered. Satin fabrics are divided into two types: Henggong and Zhigong. The front side of the Henggong fabric is mainly formed by weft yarns, while the front side of Zhigong fabric is mainly formed by warp yarns, with the weft yarns showing less than the warp yarns. Generally speaking, satin products are mid- to high-end products and have higher requirements for yarn weaving defects. Need special attention.

(4) Sparse fabrics: The warp and weft yarns have low density and tightness, such as mer yarn, voile, gauze, mosquito net cloth, mesh cloth and other light fabrics. Generally, the warp and weft yarns of sparse fabrics have less coverage and are more exposed, so unevenness, thick spots, details, and various defects can be clearly seen, so the requirements are higher.

(5) Compact fabrics: Fabrics with higher density and tightness, such as corduroy, velvet, rainproof cloth, down cloth, high-count poplin, etc. Compact fabrics have high tightness (generally around 90%) , weaving is difficult and prone to defects such as three jumps (flower jumps, yarn jumps, and star jumps); the cloth surface is required to be smooth and smooth, and it also has higher requirements for evenness and knotting. In tight fabrics, the color contrast of weft yarns is enhanced, and the probability of yellow and white yarns increasing accordingly.