How to avoid losing elasticity of elastic jeans

2020-11-20 1045

The so-called elastic denim refers to the fact that a certain percentage of elastic fiber is added to the weft during the production of denim, which will have a certain elasticity when wearing, and the body feeling will be more comfortable.


High elastic denim fabric


High elastic denim fabric的经纱使用了聚氨酯纤维与聚酯纤维的空气包覆纱或捻纱,利用织物工艺的设计,与以往商品相比伸长性能提高了40%,伸长后的恢复性能提高了30%,同时减轻了穿着时的紧绷感,还能防止高弹牛仔面料变形及膝盖鼓包,维持贴身效果。此外,该面料的染色与后整理工序与一般商品相同,且不损害弹力牛仔裤的做旧感。面料克重规格约227~283克,颜色有靛蓝色、黑色及用于成衣染色的白色。


Four-sided elastic denim


The fabric structure of the four-side elastic jeans is to use spandex elastic yarn to give the fabric a certain elasticity. Generally, the elastic fabric containing spandex has warp elasticity, weft elasticity and warp and weft two-way elasticity. The four-sided elastic fabric is both warp and weft elastic, and its elastic elongation is usually 10% - 15%, and the content of spandex in the fabric is 3%.

针织牛仔布厂

Why does spandex split?


1. Spandex is a kind of chemical fiber, which is obtained by adding elasticity after spinning. When spinning chemical fibers, they are usually combined by several single fibers and then wound into rolls. In order to eliminate static electricity and increase the stability and closure of the tow, it is often oiled, which is the process of adding an oil tanker in the silk route. The chemical fiber without oil will not only bifurcate, but also be easy to damage and break. In the post-processing, there will also be problems such as floating wire and insufficient strength. This is one of them.


2. The machine bag may be several kinds of chemical fibers wrapped together to make the wrapped yarn, which is one of the uses of chemical fiber DTY yarn, such as spandex, nylon, or cotton thread, etc. They will friction and generate static electricity under the high-speed operation of the roller.


Elimination method:


1. It can increase the humidity of the processing workshop environment, which is generally controlled at about 60%.


2. It can analyze whether the purchased spandex is not oiled and contact the supplier for confirmation.


3. Check whether your wrapping process is suitable.


Cause analysis and improvement scheme of denim fabric losing elasticity after washing


High elastic silk materials are more and more common in denim fabrics, and the quality of elasticity directly determines the progress of denim washing process. In addition to its poor quality and easy to lose elasticity, elastic denim clothing will also be affected by many external factors. Elastomeric denim products often lose elasticity in the process of garment making and washing, which is mainly caused by the following problems:


1. Generally, the drying temperature of denim fabric of elastic silk is required to be lower than 60 ℃. Too high temperature will damage the elasticity. Therefore, elastic protector should be used during the pretreatment of denim before washing, which can prevent the denim fabric from being damaged due to too low elasticity, and can also properly reduce the risk of breaking elasticity.


2. The spinning speed of the denim washing machine is too fast and the mechanical force is too large, which will cause the fabric to lose its elasticity. Therefore, it is necessary to shorten the time as far as possible or use soaking and other methods to be too soft, and maintain appropriate machine speed and rotating speed to reduce the risk of breaking the elasticity.


3. When the denim clothing is washed too soft, the temperature of the water in the tank is too high or too long, the fabric will degrade and break, making the fabric lose its elasticity, so pay attention to control the appropriate water temperature.


4. Due to the different formulations of softeners and silicone oil from various auxiliary manufacturers, some softeners and silicone oil may damage the elasticity, so it is necessary to select the correct softener and ensure the appropriate dosage.


5. Then comes the sewing process. The needles used in the process of jeans sewing can be divided into manual needles, called hand sewing needles; Needles for sewing machines are called machine needles; And other needles for sewing or marking. In the process of garment sewing, it is difficult to master the sewing of fabrics with high elasticity, which is also difficult to master for the sewing machinists. Because too thick needle or poor sewing will lead to the breaking of spandex fabric, blistering and deformation. Therefore, when sewing elastic fabrics, it is necessary to use a round needle tip machine needle, especially not to use too thick needle, to avoid a large number of broken fiber threads.


Important tips about elastic denim rinsing and corresponding ph value:


When there are products that need to be rinsed, special attention should be paid to adjusting the ph value of the bleaching water. If NaOH (caustic soda, caustic soda) is too small, it will lose elasticity due to the brittleness of the bleaching water; If the caustic soda is too much and the ph is too high, the ester bond in the polyurethane will be degraded and lose elasticity. Therefore, the pH value is 11-12, which should not exceed 12. At the same time, the temperature should not be too high to reduce the loss of spandex, and the control temperature should be less than 45 ℃.


The particularity of denim clothing style determines the particularity of its washing and dyeing production process, which includes fiber raw materials and spinning, denim yarn sizing and dyeing, denim fabric finishing and other aspects. The raw materials and finishing methods of denim products are changing with each passing day, especially the development of various functional dye auxiliaries is leading the denim products towards personalization and functionalization.


In order to improve the competitiveness of denim products and reduce the problem of loss of elasticity of denim products after washing and dyeing, it is necessary to analyze the fiber and fabric from the source, test all kinds of washing and dye additives before production, set good technology, strengthen the operation and management of front-line staff during production, and find problems in time to improve product quality.

The article originates from the knitting denim factoryhttp://www.hsbyfz.com/