Basic popularization of textile science: interpretation of gray fabric printing and dyeing processing issues

Appearance: It mostly occurs on E/R blended chemical fiber fabrics. After coloring, there are oil drop-shaped spots, which are slightly darker than normal parts. When viewed with a magnifying glass, the tips of the piles in the dark-colored areas of the fabric appear to be tiny beads, and there are more piles than the normal areas.

Cause: This is caused by uneven singeing. In the heavily dyed areas, the plush cannot be fully burned out, and becomes a melted mass at the tip, which has strong color absorption, so it is colored. Thicker.

(2) Poor penetration spots

Appearance: After coloring, the cloth surface appears in the shape of dark and light clouds.

Cause:

1). Insufficient desizing, or wax and other substances removed after processing are attached to the fabric.

2). During bath dyeing, the liquor ratio is too small and the heating rate is too fast, causing the coloring liquid to gel.

(3) Refined spots

Appearance: During the scouring process, the non-fibrous substances in the fabric dropped from the scouring are combined with the scouring agent, and then mixed with the lint dropped from the fabric, and adhere to the surface of the fabric. There are irregular flaky yellow marks on the cloth surface. If you scratch it lightly with your fingernail, short lint and debris will fall off.

Cause:

1). The scouring agent is easy to condense at room temperature.

2). When refining in a refining kettle, the water washing is not sufficient, or the washing temperature is low.

3). In continuous refining, there are sediments accumulated in the refining chamber, or there is too much foam in the refining tank and the roller surface is unclean.

(4) Practice and break holes

Appearance: The natural color cotton cloth is normal. After hydrogen peroxide bleaching, the warp or weft yarns on the cloth surface are broken, forming small holes.

Cause: There is rust on the cloth, or the bleaching bath water contains iron ions. During the bleaching process of the cloth, it is rapidly oxidized with hydrogen peroxide, causing the yarn to break.

(5)色花

Appearance: The cloth surface has irregular flakes of color.

Cause: The desizing and refining of the pre-treatment project were not completely completed.

(6) Fog spots

Appearance: Flaky stains, varying in depth and shallowness, with unclear outlines, varying shapes and sizes, not concentrated in locations, and with no definite rules.

Cause:

1). The fabric to be dyed is splashed with sewage or other chemicals.

2). If the fabric is not dried immediately after bleaching and is accumulated on the cloth cart for a long time, some fabrics will have air-drying watermarks.

3). The natural cotton cloth is stained with oil stains, and traces remain after scrubbing with strong detergent during inspection.

(7) Color difference

Appearance: The color of the dyed or printed fabric, the finished product, or the color of the printed pattern does not match the specified color
are exactly the same.

Cause:

1). The sample used for the specified color sample is too small, and the color matching after proofing cannot be exactly the same.

2). When preparing coloring liquid or printing paste, weighing dyes and additives is not accurate enough.

3). The manufacturing process and sampling conditions did not fully match, and no empirical corrections were made.

(8) Tank color differences

Appearance: For large quantities of fabrics, the fabrics are colored in several vats or in one vat. If they are not colored in the same vat, the color will be finished.
The difference between shades.

Cause: Although each cylinder has the same type, its functions will be slightly different. In the coloring process, the conditions of each operation are not exactly the same.

(9) Yin and Yang Color

Appearance: Full-width dyed fabric, there are color differences between the front and back sides.

Cause:

1). The pressing roller comes out of the edge of the cloth, and the direction of movement of the cloth is not in the same plane as the pressing line.

2). When pre-drying after press-dying, the heat received by both sides of the fabric is different.

3). The two sides of the fabric receive different wind speeds during resin finishing.

(10) Color difference between left and right

Appearance: Full-width fabric, the color gradually becomes darker or lighter from the left edge to the right edge. Fold the two fabric edges
In contrast, there is a significant difference in color.

Cause:

1). The suction rate of the roller of the dyeing machine gradually becomes larger or smaller from left to right.

2). The printing roller roller or roller outline is poorly engraved or made.

3). The pressure on the left and right sides of the printing roller or steel roller varies.

4). During pre-drying, color fixing or resin finishing, the temperature or wind speed in the left and right sides of the box is different.

(11) Medium thin, medium thick

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

1). In the open-width cross-winding coloring machine, the curvature of the spreading device is not appropriate, causing the cloth to absorb dye liquor at an inconsistent rate. The temperature in the dye bath is inconsistent at both ends and the center. Adding new coloring liquid is uneven.

2). In the liquid flow dyeing machine, the fabric circulation speed is slow and the heating rate is fast.

3). In the open-width continuous coloring machine, the suction rate between the center of the roller and the two ends is inconsistent. During drying, the temperature and wind speed are not uniform at both ends and in the center. During the continuous coloring process, the tension on the cloth body is uneven.

4). The center and both sides of the fabric formed during pre-treatment are inconsistent.

5). When roller or roller printing is performed, the center of the pressure applied is inconsistent with the two ends.

6). The resin is not processed immediately after coloring, or the resin is not completely dried after application, causing accumulation for a long time.

(12) Color difference between head and tail

Appearance: A group of fabrics containing several or dozens of pieces. After being continuously dyed under the same set conditions, the colors of the fabrics dyed at the beginning and end will have different shades.

Cause:

1). During the pre-treatment process, a batch of fabrics undergoes desizing, scouring, bleaching, silk finishing, setting, etc. before and after.

2). When dyeing in open-width rolls, the dyeing rates of the used combinations of dyes are inconsistent, the cloth guide and rolling methods are inappropriate, the dye is added incorrectly, and the coloring temperature is improperly controlled, all of which will cause damage to the end and end of the roll. Color differences.

3). During continuous coloring, the suction rate changes, the stability of the coloring liquid is poor, and the temperature during drying gradually changes.

4). If the compatibility of dyes and additives used together is poor, uneven layers of dye particles and water will occur. Due to capillary action, water first enters the fiber, causing the concentration of the dye solution to change, resulting in color differences between the beginning and the end.

5). When using ice dye for coloring, the dye will slowly hydrolyze during the long-term dyeing process, which will also cause color differences between the beginning and the end.

(13) 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 on the surface of the fabric to change.

Cause:

1). The pressure suction rate set during pressure dyeing is too large.

2). When preparing the dye solution, too much dye is used, that is, the concentration of the dye solution is too high.

3). Leave it for too long after coloring and before drying.

4). The drying speed is too fast.

5). No dye migration preventive agent is added, or the amount added is insufficient.

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