Some of the synthetic fibers are polyester, nylon, polypropylene, acrylic, kevlar. Viscose is regenerated fiber where cellulose as a base is used and then dissolved in one way or the other and then spin into a fiber. Finishes that are specific for synthetics are heat setting, antistatic finish and deweighting. Thermoplastic material becomes pliable at a high temperature and then it solidifies upon cooling. This process is reversible.
Thermoplastic fibers shrink and that is akin to a relaxation process where the molecule that was already stressed shrinks to relax. This is a thermodynamically feasible process where the entropy increases. It also involves the development of crystalline structures that are responsible for reducing the internal energy which is also good a thermodynamic process to make systems more stable. This morphology which develops during this process of heat setting can affect the dyeability. A small temperature change can change the dye uptake.
There is something called a triboelectric series, various types of electrically non-conducting materials. They behave like dielectrics and they develop charge either positive or negative based on their surface based on the ease with which the electron could be transferred. Gases consist of neutral molecules thus they are good insulators. Spark is the production of light and sound on electric discharge. Electrostatic discharge results in discomfort to a user such as clinging, dirt attraction and shock. In general, polyester is likely to develop more charge than cotton fabrics. Carbon fiber, ICPs, polyaniline and polypyrrole are inherently conductive non-metallic yarns. The spin finish on synthetic fibers
Low liquor application means using less amount of water for the application of chemicals. In the context of textile chemical processing, one should consider water and energy consumption as well as the environmental impact. There are different liquor application techniques such as pad-transfer process, one, two or three bowl mangle, Roberto roll, spray technique, foam finishing and kiss roll technique.
There are many processes in the textile finishing and one of them is the wet-processing unit where hot heat is generated. To not let the heat go to the environment, one should install heat exchangers. There are different heat exchangers available such as tube heat exchanger, recuperators, heat wheels and heat-pipe sealed tube type exchanger.
A calendar is a series of hard pressure rollers used to finish or smooth a sheet of material such as paper, textiles, or plastics. A friction calendaring machine is used to make a fabric shinier and smoother. An embossing calendaring machine is used to give some shape or design to a piece of fabric. Raising and brushing machines are used to raise and brush fibers. Sanforizing is a controlled compressive shrinkage process. After sanforizing, the residual shrinkage of woven fabric may be zero. Cylinder and festoon drying machines are used as drying is an essential process in every wet processing sequence. Stenter is used for drying, curing, thermosol dyeing, heat setting, dimensional stability and control.