Método para controlar la estabilidad del ancho de los pantalones vaqueros elásticos

hilos elásticos

Denim is one of the most popular apparel fabrics in this century, and its output currently ranks among the top of a variety of apparel fabrics. In recent years, due to the improvement of people’s requirements for clothing comfort, the development of stretch denim using spandex’s excellent elasticity and elastic recovery has become a popular trend. Stretch denim in the production process width stability is difficult to master, manufacturers often due to product width is not required and downgrade, resulting in economic losses. Therefore, how to control the width and stabilize the size is a very important issue. This paper analyzes and discusses this problem from the raw materials, weaving process, dyeing and finishing process in several aspects, from which to find the solution and effective feasible measures, so that the elastic denim fabric to obtain more stable width.

Weft Yarn Selection

Generally speaking, the elasticity of stretch denim mainly depends on the elasticity and quality of yarn. The structure and performance of different elastic yarns will have different degrees of influence on the elasticity and shrinkage of the fabric, therefore, to control the width of stretch denim fabrics, the first step is to reasonably select the weft elastic yarn.

  • Choose the right type of stretch yarns At present, the most widely used elastic yarn has three forms, spandex core yarn, spandex twisted yarn, spandex covered yarn. Among them, the core yarn has good elasticity, but the strength is low, the significant feature is that the core yarn is not exposed under the state of tension and stretch, good dyeing effect, and soft touch. The elasticity and strength of twisted yarn and covering yarn are higher, but there is the phenomenon of exposed core, which is not suitable for dyeing dark colors, and the feel is hard. Stretch denim belongs to the low elasticity fabric, in order to better control the width, its elasticity shrinkage should not be too large, and at the same time consider the dyeing effect and feel, so choose the core yarn is good.
  • Choose spandex yarns with fine threads Spandex yarn specifications have a great impact on the weaving shrinkage. The finer the spandex yarn, the smaller the elasticity, elastic elongation and shrinkage, the smaller the spandex yarn draw times are also small, the smaller the fabric elastic elongation and shrinkage, the smaller the weaving shrinkage. Therefore, should choose spandex yarn finer core yarn, in order to reduce weaving shrinkage, control fabric width.
  • Choose spandex yarn with lower draw multiplier The reason why the elastic silk has elasticity, because the processing of spandex silk for the drafting. The size of the elasticity depends on the size of the draw multiple, the larger the draw multiple, the greater the elasticity of the yarn, the greater the weaving shrinkage. The higher the draft, the greater the yarn elasticity and the greater the weaving shrinkage. If the draft is too high, the spandex yarn is easy to break, and the products are not easy to handle in the post-processing. The higher the draft, the smaller the spandex content. Generally, spandex manufacturers try to increase the draft of spandex in order to reduce the cost. As a user of elastic yarn, should have a clear understanding of this. When choosing weft yarns for stretch denim, we should try to use spandex stretch yarns with lower draw multiples to reduce shrinkage and control width.
hilos elásticos

Issues That Should Be Paid Attention To In Weaving Process Design

  • Tension control of the process tension should be uniform The size of the tension should make the spandex core yarn outside the fiber straight, and the core of the yarn does not exceed the spinning stretch times. Stretch denim generally belongs to the weft elastic fabric, roll the weft should be avoided when the tension difference, weft yarn cylinder in the yarn library should be placed about 8 hours, so that its surface temperature, humidity and weaving workshop is similar to the use of natural twisting is good. Weft should make the weft yarn back winding tension uniform, tension size is appropriate, if the use of double weft rapier loom, the two weft yarn tension must be the same size, and the size of the cylinder must also be the same, in order to avoid the weft yarn tension difference, resulting in different widths and fabric widths of the elasticity is not the same. In order to ensure the width of the fabric, to appropriately increase the side of the expansion and contraction of the role of the side support, to enhance the weft stretch tension. Under the condition of not affecting the opening clear and fabric style, in order to prevent the weft shrinkage is too large, reduce the warp breakage, elastic denim on the machine tension should be small. Stretch denim throughout the weaving process tension control is very important, stable and uniform tension is to ensure that the normal weaving and stabilization of weaving shrinkage of the basis, so as to ensure that the blank fabric width stability.
  • Reasonable design of fabric width Due to the elastic retraction of spandex yarn, spandex elastic fabric will shrink after dyeing and finishing, so the elastic fabric width should be carefully designed. Many factors affecting the contraction, with the type of fiber, yarn count, yarn coefficient, fabric structure, fabric organization and process parameters.
Desizing Process in Textile

Stabilizing Fabric Width In Dyeing And Finishing Process

In order to make stretch denim fabric achieve certain elasticity, dimensional stability, the appearance of the fabric flat style, dyeing and finishing process in the process conditions and equipment are very important.

  • Dyeing and finishing process Stretch denim dyeing and finishing process is generally: blank, desizing and washing, drying, stenting heat setting, other processing (chemical rinsing, pickling, soft treatment), mechanical shrinkage. Containing spandex elastic denim dyeing and finishing process, must pay attention to the difference between the dyeing and finishing characteristics of its composite and separate fiber dyeing and finishing. Pay attention to the tension in the process, 100 ° C above the presence of water under the conditions will damage the spandex fibers, therefore, to carefully select the process conditions.
  • Determination of desizing process Cotton elastic denim selection of enzyme desizing agent is ideal. If the sizing agent contains other components and is not suitable for enzyme desizing method, can refer to the normal cotton desizing method, but can not use sodium bromite as desizing agent. Desizing process should focus on the choice of desizing temperature, enzyme desizing temperature of 40 ~ 55 ° C is appropriate, the general desizing temperature of 80 ° C or so.
  • Determination of heat setting process As spandex-containing fabrics with retraction, whether the process can meet the requirements of commodity stability (fabric weight per square meter, stable fabric length and width, etc.) is very important. Therefore, the heat setting process is a very important and critical process in the dyeing and finishing of elastic denim. Containing spandex after the machine, the width direction of the retraction rate of up to 40% or so, resulting in the blank fabric into a highly elastic narrow thick fabric. The use of heat-setting conscious control of its elasticity, the spandex molecular structure can be part of the stereotypes into a new structure, in the elongation state, so that the spandex filament to generate a finer core yarn, but the equivalent of the elasticity of the fiber is unchanged. Thus heat-setting can obtain: reduce the elasticity of spandex; reduce the spandex content per unit area; reduce the total elongation of spandex effect. To achieve the control of shrinkage, the requirements of the fabric width. Stretch denim fabric width and the appropriate elasticity need to be realized through heat-setting, and the effect of heat-setting is determined by the heating temperature, time and the degree of expansion when setting. General cotton stretch denim heat setting temperature to not more than 150 ° C is appropriate, wool stretch denim can be higher, usually 175 ~ 190 ° C, dry heat treatment time 30 ~ 80 seconds. Thermal sizing efficiency is generally controlled at 85% to 90% as good, the degree of expansion when sizing is greater than the width of the finished product 5% to 10%.
finishing process


In the production of stretch denim, in order to effectively control the fabric width, it is recommended to take the following measures:

  • Reasonable selection of weft stretch yarn, generally choose spandex filaments finer, draw multiplier smaller package yarn;
  • Reasonable control of tension in the weaving process, so that the upper tension is small, the weft tension is uniform and appropriate size;
  • Pay attention to the effect of heat-setting in the finishing process, the appropriate heat-setting temperature should be so that the cotton stretch denim control at 150 ° C, wool stretch denim control at 190 ° C or so, the degree of expansion of the stereotypes is greater than the finished width of 5% to 10%, to stabilize the size of the width of the cloth.

Width control is a very key issue in the production of stretch denim, the methods mentioned in this paper still need to be studied in practice, improve and enhance, and further explore more reasonable, more effective control measures to improve the production process of stretch denim.