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Burning
In order to reduce the hairiness of the fabric surface and get a neat fabric surface, the fabric made of modal fiber should be burned. After this treatment, the pilling may be greatly avoided during processing or in the future application.
Depending on the gravity of the fabric
c and the blended yarn, this process needs to be done with the fabric in a free state or on a cooling roller. When designing to circular knitted fabric processing, the fiber/yarn blend should be taken into account, e.g. hairiness on the sides of cellulose fibers, which must also be treated with flame.
Desizing/rinsing
During the roll dyeing cold stack treatment, it should be noted that the fabric needs good sewing action; finer sewing threads need to be used, and these measurements should help minimize sewing marks. Dye uptake should usually be high and the rolls should be raked at low tension, which will help prevent visible sewing marks and ripples. The fabric must be cool and even, and the fabric should take between 1.5 - 2 seconds from dye treatment to press roll impregnation. The deposition of the fabric makes it incompletely swollen, which will lead to the formation of wrinkles that will remain visible after dyeing.
The composition of the dye bath for the treatment process can usually be adjusted to its formulation to suit the previous fabric application. For pretreatment of fabrics the one-step method, which includes desizing, cooking, bleaching and alkali treatment, is an excellent method and can be easily used for knitted fabrics. If knitted fabrics require rope treatment, high solubility sheets are required after hot water rinsing, and boiling and bleaching for thorough removal of different finishing agents.
Bleaching
For bleached fabrics or cotton-type yarns, we recommend using peroxide bleaching. For pure white or blended yarn fabrics that are difficult to dye, a second of reductive bleaching will give the required whiteness, in which case the fluorescent brightener in the reductive bleaching solution will complete the treatment of the product in question, while the addition of salt will play a role in the better affinity of the fluorescent brightener. Since not all fluorescent brighteners have good affinity for micro modal, corresponding choices must be made to adjust the stability of the substance to suit these products.
Special treatment with alkali
In order to get a better dyeing effect, enhance the shape stability and reduce the pilling of modal fiber fabrics, different alkali treatments can be applied.
1) Caustic soda: (standard formula)
45g/L 100% sodium hydroxide (e.g. 7Be)
3g/l Léofen LG (BASF)
Temperature 25℃~30℃, continuous
Impregnation absorption rate 120%
Impregnation time 2 min
Guiding cloth under low tension
Washing: start with hot water
2）Sandoflex-A-treatment (woven fabrics must be pre-cleaned on the mill or roll dyer)
Standard formulation.
330ml/litre Potassium hydroxide at a concentration of 50%
50ml/l SandoflexA (pure)
Temperature 25-30 degrees continuous
Absorption rate 110%
Rolling time 3-4 hours
Under low tension
Washing with water: start with hot water
Neutralizing action
3) Vesco combined batch process (rolling dyeing machine or roll dyeing machine)
Standard formulation
4g/l Vltravon GPN
2g/l INVATEX SA
6g/l Tinochlarite CBB
40g/l 100% sodium hydroxide
15ml/litre 35% hydrogen peroxide
Temperature 25-30 degrees continuous
Absorption rate 110%
Rolling time 12-16 hours
Under low tension
Water washing: start with hot water
Neutralizing effect
During the V--C--B treatment, a number of effects related to the dyeing effect are produced, both in terms of shape stabilization and reduction, but also including the bleaching process.
Drying
Regardless of whether the completion of this treatment requires the use of chemicals, drying should be carried out at a relatively low temperature, not exceeding a maximum of 130°C, with a residual moisture content of 8% to 10%, although this depends on the degree of blending, taking into account the characteristics of cellulosic recycled fibers - shrinkage after drying -- in its proper treatment, it is necessary to operate the modal fabric on a dryer without tension. One of the advantages of the stenter is the clarity of the design to the overfeed device, as well as the adjustment of the sub-width.
As a cellulosic fiber, it can be dyed with all the dyestuffs that can be expected.
Reactive dyestuffs are particularly suitable for this purpose - also because they offer the widest range of dyestuff options, making it possible to obtain good homochromatic dyeing shades when dyeing cotton blends. The exception to this rule is for some macromolecular dyestuffs, which usually react less strongly to modal fibers, and a large number of direct dyestuffs exhibit this property.
The fiber fineness of modal has only a slight effect on the affinity speed of the dye and the dyeing rate compared to various synthetic fibers. However, the effect of fiber fineness on the spectroscopic properties of dyed fabrics is still evident. Modal fabrics will have a greater light color effect compared to fibers made from normal fiber fineness, especially after the dip-dyeing stage. In order to balance the physical effects of the microfiber, we recommend that the fabric be pretreated, if possible, using a specified process and treated with alkali. In this case, the affinity and the dyeing effect will be enhanced and the abrasion resistance of the micro modal will be improved after intensive dyeing.
Direct printing with reactive dyestuff, which improves the surface spectral effect will produce a light color effect. Again this can be corrected by pretreating the fabric with the appropriate alkali. In addition to the conventional process applicable to viscose fiber or modal fiber fabric printing, also applies to micro modal fiber products.
As shown below.
Urea in the printing slurry. (Green or turquoise color)
Highly saturated steam during thermal characterization
Additional moisture application facilities prior to steam entry will likewise have a positive effect when designed to the dyeing effect of micro modal fiber products, and will reduce the amount of urea used accordingly. With regard to fabrics made of pure modal fibers, the additional moisture feeding can be limited to 20%, while blended yarns with cotton are limited to 15%.
Due to the swelling of the cellulosic regenerated fibers, the finished product exhibits repeated dimensional changes when designed for dry/wet treatment (household washing), which also applies to the pretreatment of the fabric with alkali, which in principle has a better shape stability than the fabric without alkali treatment.
In order to limit this, the swelling of the fibers must be reduced and the cellulose crosslinker and the corresponding softener are well suited to the completion of this treatment. Compared to cotton, modal clothes have no loss of toughness (low tension is required in the pretreatment phase) and have a better finishing effect than viscose fibers. Designed to control the treatment, the step should be to dry the fabric after impregnation on a needleboard stenter with an optimal overfeed device and its maximum temperature should be 130°C.
If baking is treated as a separate process, here the fabric should be treated with the corresponding overfeed device as well as a selection of catalysts, and a crosslinking temperature of 155°C to a maximum temperature of 160°C is necessary to ensure this.
The mechanical pre-shrink finishing as well as the hot press pre-shrink have an equally positive effect on the appearance, feel and washability of modal fabrics compared to their effect on cotton and viscose fibers.
Generally speaking, modal products are much less difficult to process than TENCEL products, because modal products do not have the problem of original fibrillation, no special requirements for printing, dyeing and post-treatment machinery, the ability to process cotton products and equipment can be processed on modal products, but due to the special properties of the fiber, the following issues need to be noted when handling and processing.
We can not use enzymes to reduce the lint of modal products. Because modal fiber itself has a very tight surface layer and the diameter of the surface medium stomata is smaller than the diameter of the enzyme, so the enzyme cannot penetrate into the fiber to split the cellulose molecules and clean the surface of the fabric.
modal fibers are finer than cotton fibers and do not contain the same three-dimensional curl as cotton. In the case of wet treatment, more fiber ends are freed from the yarn. There is a tendency to produce surface hairiness. Each process should try to keep low tension and low speed to reduce friction and the generation of hairiness.
Dyes and processes applicable to cellulose fibers (such as cotton) can be used to treat modal fibers.
Appropriately increase the twist of yarn or use cyclo-spun yarn;
Increase the density of the knitted fabric and reduce the stitch length;
burnt wool is the best way to reduce pilling, but because the softness of MODEL fabric has a certain impact, needs to be carefully selected;
the mercerization process is best not to use, due to the knitted fabric mercerization by the tensile force and wet friction being stronger, while the alkali on MODEL fiber alkali-soluble up the role of the original fibrillation, a combination of these two points of action so that the fabric pilling strengthen;
the use of additives: in the bleaching process adding certain additives such as an anti-pilling agent, and bath softener is beneficial to prevent pilling; dyeing and finishing process add bath softener such as Nissan D-58OH silicone to reduce the friction between yarn, and fabric and dyeing machine, while you can control the fiber from the yarn leak out of the tail end, thereby reducing the chances of pilling.
The role of softener is to obtain a soft effect by reducing the friction between fiber and fiber. Softener must meet the following conditions: a. Reduce the coefficient of dynamic and static friction between fibers; b. Softener has good resistance to washing. This will increase the abrasion resistance and washability of the fabric, which in turn will improve the pilling and pilling.
resin finishing: the use of resin-based additives by rolling and pressing, so that the hair feathers are inverted, and fixed on the surface of the yarn, to prevent pilling has a very good effect;
after the dyeing and finishing process is determined, appropriately increase the bath such as 1:20 or 1:40, and shorten the time by improving the process curve, reduce the opportunity for fabric interaction, can also reduce the occurrence of pilling of MODEL fabrics;
equipment selection: it is generally best to use loose processing. And continuous type production line on the fabric rolling stick pressure and stretching force is large, easy to wear pilling, should not be used.
