First, flaw characteristics: Dyed products derived from different shades of color, shade is different.
(1) the same batch of color difference: the same batch of products in a color number between the product box and the box, between pieces and pieces, between the package and the package, there is a color difference between the match and the match.
(2) with the same color difference: the same product in the left there is a color difference or before and after a color or positive and negative color. Chromatic aberration is one of the common defects and multiple flaws in the dyeing and finishing plant, seriously affecting the quality of finished dyed products.
Second, the causes: all kinds of fabric fiber composition is different, the type of dye used in dyeing and process equipment is different, coupled with dyeing process has different requirements and characteristics, resulting in defects in the reason and performance is not the same.
Color difference in the appearance of a variety of performance, but the reason, mainly in the following categories.
(1) uneven distribution of dyes in the fabric: dye fixation before, if the uneven distribution of various parts of the fabric, the color must be formed after fixing color.
The main reason for this phenomenon is:
① fabric factors: due to different fiber properties or pre-treatment retreat, boiled, bleached, silk is not enough to penetrate, so that uneven permeability of the dye before the half caused by differences in the extent of dye absorption.
② absorption of liquid factors; due to mechanical reasons or improper operation of the structure, so that various parts of the fabric with liquid rate is inconsistent, resulting in color. Roller uneven pressure, adding dye uneven will make the fabric absorb the dye uneven.
③ pre-bake factors: Pre-bake immersion padding solution, due to the drying rate and degree of inconsistency, causing the dye migration occurred in varying degrees, the dye distribution in the fabric uneven.
(2) The degree of fixation of the dye on the fabric is different: although the dye is uniformly distributed on the fabric at an early stage, improper control of the condition (such as temperature, time, concentration of the dye, etc.) Part of the dye is not fully fixed, was removed in the post-processing soaping, resulting in color. For example, disperse dyes on both sides of the hot-melt temperature or inconsistent before and after reduction or partial oxidation of vat dyes, reactive dyes and other poor steaming conditions will cause the fabric before or after or about color.
(3) Variation of dye color light: The difference is not caused by the uneven distribution of dye on the fabric.
But due to some reasons caused by the fabric part of the dye color change, there are three general reasons:
① pre-dyeing factors: semi-finished products of uneven brightness or pH have a greater difference in the shade often caused after the color difference.
② dyeing factors: For example, disperse dye hot melt temperature is too high, so that some of the dyes become darker shade; restore the excessive reduction of dyes, but also make the difference between shade.
③ dyeing factors: in the finishing process, such as resin finishing, high temperature tentering and fabric PH value of the different, will cause the dye shade have varying degrees of change.
④ soaping: such as soaping is not sufficient, will make the hair color is not sufficient, color is not allowed.
Third, to overcome the problem:
(1) to improve the uniformity of the roll. The use of ordinary rolling pad dyeing, the surface of the roll car should be ground into a slightly larger middle diameter, slightly smaller diameter at both ends of the olive-shaped roller; a reasonable choice of rubber roller hardness.
(2) using a uniform rolling car. Production of a single species, a single color of the product, the use of olive-shaped roller to solve the color difference in the left or left is a viable solution. However, in the production of small batch, multi-species, multi-color bit variety, then because of the factors to be considered more often require frequent replacement of roller Jane. So to the use of trouble. The use of uniform rolling car is to solve the edge of color, left and right color difference is a good way.
(3) selec the appropriate equipment to improve the equipment status, so that the dyed material in the entire dyeing process can be uniform color.
(4) to improve the uniformity of fabric drying.