The old master no longer retains the subjective reasons why cheese dyeing does not occur!

Pack yarn technology: The subjective factors that cause yarn dyeing to be unreproducible are roughly the following: winding quality, processing technology, dye selection, dyeing technology, operating factors, management factors, etc.

1 The impact of winding weight on reproducibility

(1) Package weight: When dyeing by dip dyeing, the depth of the apparent color depends largely on the dye and the quilt. The weight ratio of the dye. Generally, when dyeing and loading yarn, only the number of bobbins is counted, and no additional weighing is required. Therefore, the winding weight determines the weight of yarn loading, and all loose bobbins must be weighed during winding. The production practice of many factories has proved that even without a length-fixing instrument, it is completely possible to weigh each bobbin and control the weight within the range of ±1%. Some dyeing factories use "card plates" to measure the outer diameter, but due to the large error, it should not be used. In addition, large and small tubes will also cause color difference between tubes.

(2) Package winding density: The winding density of the loose tube has a direct relationship with the resistance of the dye liquor circulation. The density is high and the resistance is high. The size of the resistance affects the shape of the dye liquor circulation resistance curve, and therefore also affects the position of the operating point of the main circulation pump, thereby affecting the circulation flow of the dye liquor, and subsequently the dye liquor circulation frequency and the number of cycles within the specified time. Changes occur, so the amount of dye dyed changes, which will naturally cause the color of the dyed object to be darker or lighter.

When the winding density of individual bobbins is too small, sometimes the yarn will be flushed out of the "groove" and sometimes the bobbin will "collapse". The dye liquor will be "short circuited" there, which will not only cause the yarn to be Flushing and dyeing will also reduce the circulation of dye liquor on other packages, resulting in lighter colors.

(3) "Eye exposure": Since the bobbin and warp beam coil are full of holes for the dye solution to pass through, "exposure eyes" will occur when the bobbin winding position is improper or the reciprocating distance is not enough. ". During warp beam dyeing, since the warp beam is placed vertically in the main kettle of the dyeing machine, when the winding is loosened, the yarn will sometimes fall due to the influence of gravity after being moistened, causing the upper end to "eyes out". The dye liquor will "short circuit" from the "open eye", which will not only cause the yarn on the end face of the package (warp beam) to be flushed, but will also affect the flow of other packages.

2 The impact of pre-treatment on reproducibility

Many dyeing factories do not pay much attention to pre-treatment. In fact, the root cause of many problems that occur during dyeing often lies in pre-treatment. The degree of impurity removal in pre-treatment, wool efficiency, whiteness, pH value after washing, hydrogen peroxide removal after bleaching, different amounts of alkali in the mercerized yarn, different gloss caused by different tensions, etc., will all affect the quality of the dye during dyeing. Dyeing. When dyeing yarn packages, pre-treatment, dyeing and post-treatment are carried out in the same dyeing kettle, and the effect of pre-treatment is also different.

Generally, dyeing factories pay more attention to the strength determination and weighing of dyes, but they pay less attention to the strength determination and measurement of other chemicals entering the factory. The concentrations of caustic soda, soda ash, and hydrogen peroxide used are not analyzed. They are only calculated according to the instructions. The dye liquor is rarely titrated. Therefore, the pretreatment effect is different, which results in differences in the color depth and hue of the dyed products.

As mentioned before, when selecting dyes, attention should be paid to their compatibility, compatibility, sensitivity and quality stability to ensure reproducibility.

3 The impact of the rationality of the dyeing process on reproducibility

Although appropriate dyes are selected, the dyeing process