Spandex Fabric Processing Precautions
Spandex fiber is a special fiber with elasticity such as rubber. From the elastic socks, pantyhose began, into a functional swimwear, tights and other sportswear, and then developed to require a high aesthetic and comfort of tight underwear, petticoats, shirts and other underwear with material. Recently, because of its comfortable wearing and design adaptability, but also quickly applied to the shirt, all kinds of fiber blended coat, knitted garments and other high-grade fabrics and high-end clothing.
The main features of spandex fabric are:
1. Spandex elasticity is very high, the general products do not use 100% polyurethane, more in the fabric mixed with 5 to 30% ratio, the various spandex fabrics are 15% to 45% comfortable elasticity.
2. Spandex fabric is often made of composite yarn, that is, spandex for the core, with other fibers (such as nylon, polyester, etc.) made of cortex made of core yarn elastic fabric, its good adaptability to the body, it is suitable for tights , No pressure.
3. Spandex stretch fabric appearance and performance and coated with the outer layer of fabric similar to the similar products.
In the dyeing and finishing of spandex, such as improper process, it will cause damage, wrinkling and other issues. So the dyeing and finishing of spandex must be around these two issues, the appropriate adjustment process to meet customer requirements.
First, to prevent wrinkle measures
1, storage methods
As the spandex in order to improve the operating performance in the spinning, in the weaving process using silicone oil lubricants and other additives. These additives with the passage of time will naturally degrade the fiber yellowing, the elasticity of the fabric decreased. "Room temperature hardening" is a potential problem that can cause lasting creases. If the fabric is stored for more than 3 months, it should be enclosed in an airtight, opaque plastic film. More important is the weaving immediately after the amplitude of the volume after the package, to avoid the chance of bending creases.
2, the type of reservation
Containing spandex knitted fabric, the machine after the fiber inside the spandex there is a certain weaving when the formation of internal stress. The purpose of the preheating is to eliminate the stress by the process of one sheet of the fabric, so that the size of the fabric is sufficiently stable to eliminate the permanent crease of the fabric in the post-processing. If the coil is formed at the time of the weaving of the cylinder and the second coil is on the left side of the first coil, the direction of the advancement of the preform should also be 7% to 10% (relative width) on the left side, be consistent.
The best scheduled scenario is:
Relaxation → steaming (no steaming hot water 80 ℃) → over feed type → (into the fabric pretreatment → stereotypes → printing).
Most of the dyeing plant because there is no steaming equipment and direct rolling into the stereotypes, when the temperature below 10 degrees (winter), the fabric is easy to produce creases. The fabric through the steam box after relaxation and then stereotypes, will receive satisfactory results. Heat setting temperature between l85 ~ 190 ℃ is better, the time 45 ~ 60 S. The molding temperature is too high, will make the fabric yellowing. At the same time if the impurities and additives on the fabric due to the impact of baking part of the degradation of its degradation of the material once the migration to the fiber inside the stains, then these marks in the post-processing is difficult to remove, stained fiber within the oil spots Will be the first adsorption of dyes, and in the process of dyeing and dyeing can not be timely precipitation of the formation of deep stains, even if the stripping re-dyeing, but also remain in the fabric, but also affect the spandex fastness. Therefore, avoid the high temperature of 195 ℃ above the predetermined type (spandex softening temperature of about 200 °), when the width of the fabric than the width of l0% to l5%, let it in the dye tank in the pre-treatment when there is a full reply, So that the fabric stress completely eliminated. Semi-finished products must be based on the original design of the process, in general, the width of the finished product width than the width of 3% to 5%, by the shrinkage control in the finished product within the shrinkage, The proportion of the magnification. If it is single knit fabric, then also need to cut the edge and the best twist control, reduce the twist caused by the printing weft. The width of the edge of about lcm, off the pulp. Not too thin or too thick, too thin to play the role should be too thick will affect the cloth near the edge of the printing effect. Paint printing due to stay in the fabric of the solid slurry will increase the square of the fabric weight, so in the width, shrinkage in line with the conditions, the weight can be lighter.
Second, the pre-treatment
Silicone oils and lubricants can degrade the dye leveling, resulting in reduced color fastness, so it should be removed from the fabric as much as possible before dyeing. Elastic fiber blended fabric dyeing before the oil residue is usually invisible, but the metal complex dye is lipophilic, that is, the oil on the cloth in the beginning of the dyeing process with their affinity. When the dyeing temperature rises, the oil is emulsified, but the dye is retained to cause irreversible stains. Spandex content of more than 5% elastic fiber pretreatment recommended the use of spandex degreasing agent to achieve the desired effect of degreasing. In order to prevent the oil back to dipping, effective washing method is to use hot water thoroughly overflow rinse, with cold water for the final rinse.
Need to print the knitted fabric should also be pre-treated to remove cotton stains and grease wax, etc., to increase the whiteness of the fabric and improve fabric hair effect, so as to achieve good printing results. Pretreatment process can be divided into two categories, namely the traditional alkali treatment and modern biological enzyme treatment, biological enzyme treatment in line with environmental processing requirements, but the current requirements of whitening or bleaching high fabric is still difficult to meet the requirements, so the conventional Alkali treatment process is still widely used, spandex fabric pretreatment after washing gradually cooling is necessary to prevent sudden cooling caused by fiber shrinkage crease.
Third, the equipment selection
In the dyeing process, high temperature and mechanical stress can cause fabric elastic loss. In order to preserve its elasticity, textiles in the elastic fiber content of more than 10% should be dyed on the slow flow jet, the elastic fiber content of less than 10% of the fabric can be stained on the air jet.