Woven fabrics - finishing after printing and dyeing - the most comprehensive interpretation of defects

oil drop spots

Appearance: Occurs mostly in E/R blended fabrics. After dyeing, there are spots in the shape of oil droplets, which are slightly darker than normal parts. Observing with a magnifying glass, the plush in the thick-colored part of the fabric has a tiny bead-like tip, and there are more plush than the normal part.

Causes: This is caused by uneven singeing, where the dyed spots are thick, the plush is not fully burned, and becomes a fusion group at the tip, which has strong color absorption, so the dyeing is thicker.

Poor penetration spots

Appearance: The dyed fabric surface is in the shape of colorful clouds.

Causes: 1). Insufficient desizing and fine pulp, or the wax that has been removed after treatment is attached to the fabric. 2). The bath ratio is too small during bath dyeing, and the heating rate is too fast, so that the dyeing solution is gelled.

Bleached Hole

Appearance: The gray cloth is normal. After bleaching with hydrogen peroxide, the warp or weft yarns are broken and small holes are formed on the cloth surface.

Causes: There is rust on the cloth surface, or iron ions are contained in the bleaching bath water. During the cloth bleaching process, it is rapidly oxidized with hydrogen peroxide and the yarn is broken.

Skilteriness

Appearance: The cloth surface has irregular flake color shades.

Cause: The desizing and scouring of the pre-treatment project have not been done thoroughly.

Mist

Appearance: Sheet-like dyed spots, some deep and some shallow, the outline is not obvious, the shape and size are different, the location of occurrence is not concentrated, and there is no certain rule.

Causes: 1). The fabric to be dyed is splashed with sewage or other chemicals. 2). Not drying immediately after scouring and bleaching, and accumulated on the cloth car for a long time, some fabrics have air-dried watermarks. 3). The greige cloth is stained with oil, which is left after scrubbing with a strong detergent during embryo inspection.

chromatic aberration

Appearance: Dyed or printed fabrics, the finished color of the dyed product, or the color of the printed pattern is not exactly the same as that specified.

Causes: 1). The sample used for the specified color sample is too small, and the exact same color cannot be achieved when matching the color after proofing. 2). When preparing dyeing solution or preparing printing paste, the weighing of dyes and auxiliaries is not accurate enough. 3). The conditions of the manufacturing process and proofing are not fully matched, and no empirical corrections have been made.

Cylinder color difference

Appearance: Fabrics in large batches are dyed in fractional vats or several times in one vat. If they are not dyed in the same vat, there will be differences in shades.

Cause: Although each cylinder is of the same type, its function will be slightly different. In the dyeing process, the conditions of each operation can not be the same.

Yin and Yang

Appearance: dyed full-width fabric, the color of the front and back sides has color difference.

Causes: 1). The pressure dyeing rollers go out of the selvedge, and the direction of cloth travel is not in the same plane as the pressure and suction line. 2). When pre-drying after press dyeing, the heat received by the two sides of the fabric is different. 3).During resin processing, the wind speeds on both sides of the fabric are different.

left and right chromatic aberration

Appearance: full-width fabric, the color gradually becomes darker or lighter from the left selvedge to the right selvage edge. Fold and compare the two selvedges, and there is a significant difference in color.

Causes: 1). The pressure suction rate of the pressure dyeing machine rolls gradually increases or decreases from left to right. 2). Improper engraving or production of printing cylinder rollers or rollers. 3). The pressure on the left and right sides of the printing cylinder roller or rolling steel is different. 4). During pre-drying, color fixing or resin processing, the temperature or wind speed of the left and right sides of the box are different.

Medium-rare, medium-concentrated (Listing)

Appearance: The color of the fabric near the edge and near the center is different in depth.

Causes: 1). In the open-width cross-winding dyeing machine, the curvature of the spreading device is not suitable, so that the absorption rate of the dye solution in the cloth is inconsistent. The temperature in the dye solution tank is not consistent with the center at both ends. Add new staining solution unevenly. 2). In the liquid flow dyeing machine, the circulation speed of the fabric is relatively slow, while the heating rate is relatively fast. 3). In the open-width continuous dyeing machine, the pressure-suction rate at the center of the roll is inconsistent with that at both ends. When drying, the temperature and wind speed are not uniform at both ends and the center. During the continuous dyeing process, the tension on the cloth body is not uniform. 4). The center of the fabric formed during pre-processing is not consistent with the two sides. 5). When printing with rollers or Luo Dali, the pressure applied to the center is not consistent with the two ends. 6). The resin is not processed immediately after dyeing, or the resin is not completely dried after applying the resin, and it accumulates for a long time.

Tailing of Ending

Appearance: A group of fabrics containing several or dozens of pieces, after continuous dyeing under the same setting conditions, the color of the fabrics dyed at the beginning and the end is different in depth.

Causes: 1). In the pre-treatment process, there are differences in desizing, scouring, bleaching, mercerizing, and setting before and after a batch of fabrics. 2). In the open-width cross-lap dyeing, the dyeing rate of the combination of dyes used is inconsistent, the fabric guide and roll method are not appropriate, the addition of dyes is wrong, and the dyeing temperature is not properly controlled, all of which will cause color difference between the beginning and the end. 3). During continuous dyeing, the pressure-absorption rate changes, the stability of the dyeing solution is not good, and the temperature during drying changes gradually. 4). If the compatibility between the dye and the auxiliary agent used in combination is poor, an uneven layer of dye particles and water will occur. Due to capillary action, water enters the fiber first, resulting in a change in the concentration of the dye solution, resulting in a color difference between the head and the tail. 5). When dyeing with ice dye, the dye will gradually hydrolyze during the long-term dip-dyeing process, which will also cause color difference between the head and the tail.

Migration

Appearance: When the dyed fabric is dried, the water contained in the fabric evaporates, and the dye moves with the water to the surface of the fabric, causing the color tone of the surface of the fabric to change.

Causes: 1). The pressure suction rate set during pressure dyeing is too high. 2). When preparing the dye solution, the dye used is too much, that is, the concentration of the dye solution is too high. 3). After dyeing, leave it for too long before drying. 4). The drying speed is too fast. 5). No anti-staining agent was added, or the amount added was insufficient.

Warp Stripe (Warp Stripe, YarnTexture Streak)

Appearance: Piece-dyed woven fabric with rain-like stripes in the warp direction. In severe cases, it can also be seen on the cloth surface of the embryo cloth. Such blemishes may show significant or insignificant differences due to the lightness and darkness of the inspection site, the direction of observation, and the distance of distance.

Causes: 1). It is formed due to the difference in the count, uniformity, twist number and cross-sectional shape of the yarn used for weaving. 2). Improper selection of dyes, especially when dyeing green, is more likely to occur. 3). If it is a polyester processed silk fabric, the desizing treatment is improper before dyeing, and the paste remains in some parts. It is less colored during dyeing, the color is lighter, and warp stripes appear.

Barry Dyeing, Filling Band in Shade

Appearance: In the weft direction of woven fabrics, or the horizontal continuous loops of circular knitted fabrics, after dyeing, the color appears as a darker or lighter band.

Causes: 1). The woven gray fabric has dense or sparse defects. 2). During weaving of knitted fabrics, the yarn feeding tension is uneven, or the number of loops is uneven. 3). Filament chemical fiber yarns with the same specifications but different batch numbers are used for weaving. 4). Chemical fiber yarn for knitting, in the process of yarn processing, the heating process temperature is not uniform.

Dye Spot

Appearance: 1). On the surface of dyed medium and light-colored fabrics, there are tiny color spots of the same color. 2). On the surface of bleached or light-colored fabrics, there are tiny color spots of other dyes.

Causes: 1). The dye is poorly dissolved, and there are still tiny particles that have not been dissolved. 2). The dyestuffs fly during transportation and fall on the fabrics to be processed. 3). When the mechanical equipment is not cleaned, after the dark color is processed, the light color is continued to be processed.

Rope Mark

Appearance: When dyed in rope shape, the fabric shrinks into a rope shape, and after dyeing, there are irregular color depth and light wrinkles along the direction of the cloth length.

Cause: When dyeing with Wenqi or liquid flow dyeing machine, the fabric is not pre-set or the setting is insufficient. During the dyeing, the scroll bar malfunctioned and stopped working. Rapid heating or cooling. Dye bath ratio is too small. The fabric is knotted etc. in the cylinder.

Padding Mark

Appearance: When the woven fabric is open-width pressure-dyeing, the fabric is folded in the warp direction between two rolls, and when passing through the pressure line, the pressure-absorption rate varies due to the difference in thickness. The folded part is slightly lighter in color than the normal one. It mostly occurs on the two ends of a piece of fabric.

Causes: 1). The fabric to be dyed has creases in the pre-treatment process, which cannot be completely eliminated when it is set. 2). The spreader of the cloth feeding device of the pressure dyeing machine failed, and the fabric could not be opened. 3). The seam between pieces is poor, with shrinkage or irregularity.

Uneven Dyeing on Selvage

Appearance: After dyeing, the color of the edge of the fabric is different from that of the fabric surface.

Causes: 1). The edge of the gray cloth is too loose or too tight. 2).During setting before dyeing, the edge of the fabric is clamped by high-temperature splints. 3). The edge of the selvage is curled during dyeing. 4). During open-width cross-winding dyeing, the winding is not uniform, and the edge of the cloth is oxidized. 5). Insufficient reduction in open-width cross-roll vulcanization or vat dyeing. 6). The pressure absorption rate of the cloth edge and the cloth surface is not consistent during the open-width pressure dyeing. 7). The washing after dyeing is not sufficient, and the medicine remains on the edge of the cloth.

Fading of Selvage or Discoloration

Appearance: The finished fabric after printing and dyeing, the color of the selvedge is different from the normal one.

Causes: 1). During resin processing, the temperature of the needle plate or plywood is too high, and the dye sublimates and escapes. 2). When using the rotary cylinder dryer to dry the fabric, the temperature is too high, and the cloth edge is too tight around the cloth cylinder.

Edge mark (Edge Mark)

Appearance: Refers to cylindrical knitted fabrics, the parts where the two sides of the tubular flat fold turn and turn, showing abnormal dyeing.

Causes: 1). The oil added during weaving deteriorates. 2). Improper or long-term storage of gray cloth, the cloth edge is changed or polluted by the action of air and sunlight. 3). When the cylinder is shaped, the temperature of the shaping frame is too high.

twenty one

drum contamination

Appearance: During the dyeing and finishing process, when the cloth passes through the cylindrical device, due to the uncleanness of the cylindrical surface, such as oil, chemicals, dyes and other filth, the surface of the cloth is polluted. The shape is mostly small flakes, and there is a certain distance between the two pollutions.

Causes: 1). There are oil stains on the cloth guide roller. 2). The pressing roller is stuck with tar-like lakes, or short fibers that fall off from the fabric and other dirt. 3). The drying cylinder is sticky with oil stains and dirt.

twenty two

Dyeing Stop Mark

Appearance: Along the weft or transverse direction of the fabric, there is a trace of 2 to 10 cm wide, darker or lighter than the normal color, and there are watermarks on both sides.

Cause: During the normal operation period of the machine, when the machine suddenly stops due to power failure, cloth rolling or other mechanical failures, the fabric is clamped between the two rollers, which occurs when the dyeing solution or reducing solution is sucked.

twenty three

Pigmentation

Appearance: The packaged finished fabric has darker spots of the same color after opening.

Cause: The dyed and finished fabrics are packaged in a sealed package. Due to the condensation of evaporated water vapor, dyes and processing agents with weaker wet fastness will cause them to move and form spot-like stains.

twenty four

printed crease

Appearance: On the surface of the printed fabric, there is a shuttle-shaped or strip-shaped area along the warp or longitudinal direction without printed patterns.

Cause: During printing, the fabric surface is wrinkled and overlapped, and the covered parts are not printed with patterns.

Printing paste cylinder pollution

Appearance: Fabrics printed on a white background are uniformly polluted by a very small amount of printing paste, mostly on rollerized fabrics.

Causes: 1). The mirror surface of the printing roller is not enough, and it is easy to adhere to the printing paste. 2). The scraper is not in good contact with the printing cylinder, or the scraper is not sharp enough because it has not been sharpened frequently. Black or dark larger patterns are most likely to be printed on a white background.