Textile Dyeing Procedures Essay Research Paper Textile

  • Просмотров 244
  • Скачиваний 4
  • Размер файла 15
    Кб

Textile Dyeing Procedures Essay, Research Paper Textile materials can be dyed at any stage of their production procedure. The main types of methods are batch, continuous, or semicontinuous processes. The method used depends on several factors including type of material (fiber, yarn, fabric, garment) type of fibers composing the material, end use of material, and the quality expected from finished product. The machinery used for dyeing application is usually made out of type 316 stainless steel. This strong material is used because of the constant ttack by the acids, bases, and other additional strong chemicals and dyes used in the process. Many fabrics also undergo printing processes to produce patterned effects. Batch dyeing is the most common method used today. In this

system, textile products are processed as individual discrete units. The dye is transferred slowly to the material from a large volume dye bath. Three basic types of application are used 1) bric is circulated through a still dyebath 2) dyebath is circulated through a material that is held stationary 3) both the dyebath and material are circulated. The most popular machines that carry out batch dyeing are becks, jet dyeing, and jigs. Dyeing becks consist of a trough with a slanted back to allow fabric to slide down into the dye. The fabric has been sewn together at the ends to form a loop approximately 50 to 100 meters long. It is controlled by a reel that pulls the fabric out of he dye bath and over an idle roll that functions to press off excess dye. The chemicals used are added

to the beck by a compartment in the front that contains a perforated divider that serves to let the chemicals be added gradually. The compartment is ated with steam to allow better mixing and provide agitation. The advantages of the dye becks are low cost, versatility, and the encouragement of yarn crimp and fabric bulk. The drawbacks are the amounts of water, chemicals, and energy used, and the pr ess may cause abrasion or distortion to the fabric. Jet dyeing machines are similar to becks in that the fabric is sewn together in loops. But in jet dyeing many loops of fabric ate threaded through guides and circulated at velocities from 200 to 800 meters per minute while a pump passes dye liqour thr gh a heat exchanger located outside the machine and back inside. The machine may be

heated or pressurized to aid in dyeing. It also uses less water and chemicals and energy than the dye beck. In Jig dyeing the fabric is moved back and forth through a dye bath by being wound from a roll on one side of the jig to another on the opposite side. This is a nonabrasive method since the fabric surface is undisturbed, and usually used for worsted f rics. This process usually takes place at atmospheric pressure, but the jig dyer at maximum can dye several thousand meters of fabric. Continuous dyeing is a system used for polyester blend woven fabrics, and also nylon carpets. In continuous systems, fabrics move constantly from one process to the other. The steady flow reduces the time of processing cutting back on inventory build p. Speeds from 50 to 100 meters per minute

are typical in this method. “The main advantages of continuous dyeing are: 1) no water pollution, 2) recovery and recycling of solvent and excess dye, 3) simple operation in changing dyeing colors. and 4) aut ation in color matching and tone adjustment with the use of a computer system and automatic weighing system.” (Lyle, 1976) One method, called padding, involves a closed system in which the solvent is recycled eliminating the problem of pollution. The fabric is immersed into a concentrated dye solution and the sent to two weighted mangles where the excess dye is squeezed o and returned back its container. Next the fabric may be steamed, or left to stand at room temperature for a few hours to allow the dye molecules to penetrate into the fibers. After this process the