Dyeing and Finishing Properties of Spunlace Nonwoven Fabric
In China, spunlace nonwovens that have known dyeing, printing, and other dyeing and finishing procedure and treatments have frequently become successful in the market and are widely used in cleaning wet wipes, medical and health, and protective apparel in the current year. The dyeing and finishing of spunlace nonwovens increase the product industry chain, improve the product's added value, and have gained consumers' favor with its fine, stiff, and washable characteristics. Therefore, our manufacturing company All Clean Natural China is actively expanding and developing their technology that is related to product increase in the various application fields of spunlace nonwovens.
High-pressure water needles are used in spunlace nonwoven fabrics to entangle the fibers into fabrics. Compared with ordinary woven textiles, they are easily deformed and not resistant to washing. Therefore, the dyeing and finishing arrangements of spunlace nonwovens are quite different from standard fabrics.
The traditional dyeing and finishing process cannot be washed with water, and the tension control during the production process should be reduced as much as possible. Thus, dyeing and finishing spunlace nonwovens are generally carried out by open-width padding, spraying, scraping, etc.
If there is no special requirement for the fastness to wash and rub the printed or dyed spunlace nonwovens, pigment dyeing and printing can generally be used. The advantage of pigment dyeing is that it is suitable for printing and dyeing of spunlace non-woven with most fibers and a variety of fiber blends and can meet online dyeing requirements finishing of spunlace nonwovens. The mechanical process flow is short, energy consumption is low, and wastewater discharge is low. Achieve zero-emission; while the dye printing and dyeing process is longer and the industrial process conditions are relatively high, most of the dyes need to be washed to remove floating colors after printing and dyeing are rarely used in the dyeing and finishing of spunlace nonwovens.
In the dyeing and finishing process of spunlace nonwovens, spunlace nonwovens' structural properties have a particular relationship with selecting additives and formulas, process conditions, dyeing, and finishing quality in dyeing and finishing. This article mainly analyzes the influence of spunlace nonwovens' performance on its dyeing and finishing power through the following aspects.
1 Raw material in spunlace
According to the continuity of production equipment and dyeing and finishing process requirements, the dyeing and finishing of spunlace nonwovens are divided into online finishing and offline finishing. In the dyeing and finishing process, the residual rate is crucial for the dyeing and finishing process. For online finishing, the fabric's chemical moisture content before dyeing and finishing (that is, the percentage of the moisture content after spunlace dehydration and the dry weight of the material) directly affects the sizing working fluid concentration. The rolling mill's pressure does not entirely determine the reduction rate; for offline finishing, the rolling reduction rate of dyeing and finishing is mainly determined by the rolling mill's force. It also has an individual relationship with the fiber raw materials. At present, the primary fiber raw materials of spunlace nonwovens are polyester and viscose. During online finishing, the moisture content of spunlace nonwovens composed of different fiber materials after dehydration is shown in Table 1. Table 2 is for offline finishing, the rolling margin of spunlace nonwovens with other raw material ratios under the same pressure of a specific rolling mill.
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It can be seen from Table 1 and Table 2 that spunlace nonwovens with higher synthetic fiber content such as polyester have poor water absorption and hygiene properties and slow absorption of dyeing and finishing auxiliaries. Therefore, when continuous padding is used for dyeing and finishing, the speed cannot be too fast. To prevent the dyeing and finishing effect from being unstable due to uneven liquid. Compared with natural cotton fiber and synthetic fibers such as polyester, viscose fiber has good water absorption properties. Therefore, the dyeing and finishing of spunlace nonwovens with higher viscose fiber content are easy to dye through, but because the adsorption finishing agent is too fast, it will cause uneven local absorption. At the same time, the dyeing and finishing auxiliaries are easy to diffuse during drying, resulting in migration and uneven dyeing. Therefore, if necessary, a certain amount of leveling agent and anti-migration agent should be added to improve the uniformity of dyeing. Therefore, if necessary, a certain amount of leveling agent and anti-migration agent should be added to improve the uniformity of dyeing. In terms of baking, viscose fibers will turn yellow at temperatures above 170 degrees Celsius, causing white spunlace nonwovens to turn yellow or dyed spunlace nonwovens to deviate in color. Therefore, when the proportion of viscose is high, especially pure viscose for the baking process after dyeing and finishing of the spunlace nonwovens, the temperature cannot be higher than 160 degrees Celsius. When performing online finishing textile, the moisture content of the spunlace fabric after dehydration should be controlled, especially the spunlace nonwovens with high viscose fiber content. Because too high-water content will reduce the total amount of dyeing and finishing auxiliaries actually absorbed by the cloth surface, it will also cause the dyeing to become lighter and lighter. For example, a spunlace nonwoven with a moisture content of 100% after dehydration is immersed in a trough, and after saturated absorption of the dyeing and finishing auxiliary, the residual rate after passing through the rolling car is 150%. In this process, the actual spunlace nonwoven fabric only absorbs slightly more than 50% of the dyeing and finishing auxiliaries, while the auxiliaries rolled down by the rolling car are diluted by the residual moisture on the fabric surface, and the concentration is less than that in the trough. Therefore, the auxiliaries in the trough are constantly being diluted, resulting in lighter dyeing or poor finishing effects. Therefore, if the moisture content of the spunlace nonwoven fabric is too high after dehydration, it needs to be pre-baked appropriately to reduce the moisture content of the fabric surface. 2 Mass and density per unit area In the production process of spunlace nonwovens, using the same fiber materials and the same process conditions, the higher the unit mass, the greater the density (weight per unit area/thickness); for the same fiber material, the same unit mass, Process parameters such as web weight, number of layers, spunlace pressure, drying temperature and etc., will directly affect the density of the product and form products with different tightness. When the thick and compact spunlace nonwovens are dyed and finished, the dyeing and finishing auxiliaries are not easy to penetrate into the interior of the fabric, which affects the dyeing and finishing effect. Especially when dyeing with pigments, the phenomenon of "white core" is very easy to appear, that is, the surface is colored, but the interior is still white. When the relatively fluffy and light spunlace nonwovens are dyed and finished, if the tension is too large, it is easy to cause deformation of the fabric surface and destroy the structure of the spunlace nonwovens. For the pigment dyeing or printing process of spunlace nonwovens by scraping, the higher the unit mass and thickness of the grey fabric, the worse the penetration of the slurry, which is likely to cause the disharmony of dyeing or printing patterns. Even the phenomenon of single-sided patterns, the lighter the grey fabric, the more consistent the double-sided dyeing and finishing effect, but it is necessary to pay attention to the problem that the rubber roller is stained with too much slurry and is difficult to clean. Of course, the permeability of the slurry is also related to the water content of the product itself and the viscosity of the slurry. By adjusting these two factors, the requirements for printing and dyeing single-sided or double-sided patterns of specific spunlace nonwovens can be met. 3 Uniformity and flatness of fabric surface Uniformity is an important indicator to judge the quality of spunlace nonwovens, and it also has a significant impact on dyeing and finishing. Uniformity includes multiple meanings:
With the influence of the combination of raw material composition, unit mass, and thickness mentioned above in this article on dyeing and finishing, it can be known that the uniformity of the grey fabric itself is low, which will cause uneven dyeing and finishing and further amplify the unevenness of the material itself. The standard surface irregularities of spunlace nonwovens, such as burls, creases, flying, discolorations, etc. have a vital threat to the subsequent dyeing and finishing process and will cause partial dyeing and finishing. Uneven. Therefore, it is necessary to find out the problems such as frustration and flying of the grey fabric in time to avoid more considerable losses after dyeing and finishing of defective products.  |
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