Elastic fiber has entered into all aspects of people's daily life, is essential to the life of a textile and clothing materials!
Without it, there is no stockings for beautiful women; without it, there is no summer colorful swimsuits; without it, there is no highlighting the devil's body of the leggings ...... It can be said that the elastic fiber for human beings to show the body, enjoy the comfort of wearing clothing has made an indelible contribution!
Speaking of elastic fibers, we have to mention the 1962 U.S. DuPont mass production of spandex. Unlike other synthetic fibers, spandex is a special fiber with rubber-like stretch properties. Spandex fibers have been used in a wide range of sportswear, from elastic socks and pantyhose to functional swimsuits and tights, and then to undergarments such as tight-fitting undergarments, petticoats, and blouses, which require a high degree of aesthetics and comfort. Recently, because of its wearing comfort and design adaptability, but also rapidly applied to shirts, blended outerwear of various fibers, knitted outerwear and other high-grade fabrics and high-grade clothing.
The main characteristics of spandex fabric
1. spandex elasticity is very high, general products do not use 100% polyurethane, more in the fabric mixed with the proportion of 5-30%, the resulting variety of spandex fabrics have 15% to 45% of the comfort of elasticity.
2. spandex is usually not used alone, spandex fabrics are often made of composite yarn, such as spandex as the core, with other fibers (such as nylon, polyester, etc.) to make the skin made of core yarn stretch fabrics, its adaptability to the body is good, very suitable for making tights, no pressure.
3. The appearance style and taking performance of spandex stretch fabric are close to the similar products of the covered outer fiber fabric.
In the dyeing and finishing process of spandex, if the process is not proper, it will cause problems such as loss of elasticity and wrinkle. Therefore, the dyeing and finishing of spandex must be centered on these two major problems, and the process must be adjusted appropriately to meet the requirements of customers.
Since spandex in order to improve the running performance in the spinning, in the weaving process using silicone oil lubricants and other additives. These additives will naturally degrade over time resulting in a yellowing of the fiber and a decrease in the elasticity of the fabric. At the same time, spandex-containing fabrics in long-term storage will form a "cold set", so that the fabric in the post-processing of permanent wrinkles can not be eliminated. Therefore, spandex-containing knitted fabrics, in addition to reducing the storage time, it is more important to weave immediately after the opening of the flat width of the roll to avoid the opportunity to produce pressure crease.
Spandex-containing knitted fabrics, the spandex inside the fiber after the machine, there is a certain amount of internal stress formed during weaving. Therefore, the purpose of preheating and shaping is to eliminate the stress through the fabric's one sheet process, so that the fabric's dimensions are fully stabilized, eliminating the fabric in the post-processing of permanent creases. If the second coil is to the left of the first in the case of loops formed during cylinder weaving, then the direction of feed should also be 7% to 10% (relative to the width) in front of the left side during pre-shaping, so that the twist is consistent with that of the finished product.
Pre-forming
Therefore, the optimum pre-shaping program is:
Relaxation → steam steam (no steam conditions of rolling hot water 80 ℃) → super feed pre-shaped → (into the fabric pretreatment → shaping → printing).
Most of the dyeing plant because there is no steam equipment and direct rolling water into the shaping, when the temperature is below 10 degrees (winter), the fabric is prone to creases. Fabrics through the steam box relaxation and then shaping, will receive satisfactory results. Thermal shaping temperature to l85 ~ 190 ℃ is good, shaping time 45 ~ 60 S. Shaping temperature is too high, will make the fabric yellowing.
At the same time if the fabric impurities and additives due to the impact of baking and partial degradation, its degradation of substances once migrated to the interior of the fiber to produce marks, then these marks in the latter processing is difficult to remove, dyeing of the fiber inside the oil spot will be the first to absorb the dye, and in the heat preservation shift dyeing process and not be able to run out of the process in a timely manner and the formation of dyeing the deep spot, even if then stripping the color of the dyeing again, it will also be residual in the fabrics, therefore, the Avoid high temperature shaping above 195℃ (Platform Jun Note: the softening temperature of spandex is above 200°), which will also affect the fastness of spandex. The width of the shaping is wider than that of the blank fabric by l0% to l5%, so that it can have a full recovery in the dyeing vat during pretreatment, so that the internal stress of the fabric can be completely eliminated.
Pre-treatment
Need to print the knitted fabric should also be pre-treatment, remove cotton impurities and grease wax, increase the whiteness of the fabric and improve the wetting of the fabric, water absorption, so as to achieve a good printing effect. Pre-treatment process can be divided into two categories, namely, the traditional alkali treatment and modern bio-enzyme treatment, bio-enzyme treatment in line with the requirements of environmental protection processing, but at present it is difficult to meet the requirements of whitening or bleaching requirements of high fabrics, so the conventional alkali treatment process is still widely used, spandex-containing fabrics pre-treatment of the gradual cooling of the washing process is very necessary to prevent the fiber from shrinking caused by the sudden cooling produces creases.
Semi-product shaping requirements
Semi-products of the shape, must be based on the original design process, generally speaking, the shape of the width of the width of the finished product is wider than 3% to 5% or so, the warp shrinkage control in the finished product within the required shrinkage, the elongation of the cloth is equal to the tracing of the enlarged ratio. If it is a single-sided knitted fabric, then you also need to paddle cutting edge and the best twist control, to reduce the print weft skew due to twist. The width of the sizing edge is about lcm, with a break point sizing. Should not be too thin or too thick, too thin to play a role, too thick will affect the effect of printing near the edge of the cloth. Coating printing due to stay in the cloth surface of the solid pulp will relatively increase the square meter grams of fabric quality, so in the width, shrinkage rate in line with the conditions, the grams of quality can be a little lighter.