Defect form:</p
There are regular stains on the fabric that are basically similar in shape or size, or irregular in shape and size, and are of the same color as the dyed fabric. This defect is difficult to repair;</p
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Cause: </p
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1. Condensation of dye<br /
1) Direct collision of dye molecules aggregates into large dye aggregates;<br /
2) During the color development (fixation) process of dyeing, the dye molecules generate strong polymerization force, causing the dye to agglomerate;</p
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2. Tarring of dyes: the process in which dye particles and surfactants condense into tar-like substances under high temperature conditions;<br /
1) Poor pre-treatment and insufficient cleaning. Fabric oils, lubricants, etc. and grease are brought into the dye bath. Under high temperature conditions, they come into contact with hydrophobic dye particles and form tar-like substances after adsorption; <br /
2) When using a surfactant with a cloud point lower than the dyeing temperature for pretreatment, if it cannot be washed clean or the dyeing temperature is too high, the non-ionic components will lose their water solubility and precipitate hydrophobic oil particles, which will later form color stains; <br /
3) When using non-ionic and anionic composite high-temperature leveling agents for dyeing, if the dosage is too high, tar substances will also be formed;<br /
4)采用某些阴离子型活性剂染色时，如溶解不良，也会形成色渍。
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3. Contamination of fabrics by lakes<br /
1) The lake brought to the fabric by the dye solution foam, causing stains;<br /
2) When the fabric enters the developing liquid, the dye liquid it carries flows into the developing bath, and is hydrolyzed and oxidized to form a lake, which also floats on the liquid surface. If you are not careful, it will contaminate the fabric and form color stains;</ p
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Ways to overcome</p
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1. Strengthen the pre-treatment of fabrics, remove oily substances, and wash away non-ionic components; <br /
2. Measures to prevent the aggregation of soluble vat dyes:</p
Mainly to increase the oxidation speed of the dye liquor and avoid giving the hydrolyzate products a chance to agglomerate;<br /
1) The stronger the acidity of the color developing bath, the faster the dye will be hydrolyzed and oxidized;<br /
2) The higher the temperature of the color bath, the faster the oxidation rate;<br /
3) Add ammonium metavanadate to accelerate its oxidation reaction;</p
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3. Measures to overcome the agglomeration of disperse dyes<br /
1) Choose dyes that have less cohesiveness at high temperatures;<br /
2) Select leveling agents and dispersants with excellent performance;<br /
3) Correctly master chemical mixing operations;</p
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4.Measures to prevent stains<br /
1) Try to reduce and avoid the generation of color lake;<br /
2) Diffusion agents should be added to both the dyeing solution and the developing solution to effectively eliminate floating colors;<br /
3) Before color development, the foam on the liquid surface must be driven to the corners and stirred to spread the color lake;
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