Manufacturing Process of Synthetic and Regenerated Fibers

You are currently viewing Manufacturing Process of Synthetic and Regenerated Fibers

What are Synthetic and Regenerated Fibers?

The term “synthetic fiber” refers to fibers made from polymers created from chains produced by a controlled chemical process. Synthetic fibers are the result of intense research that has been carried out to improve the properties of natural fibers. found natural fibers both animal and vegetable. They are created by extruding polymeric material of synthetic origin, by spinning in water or air. These fiber-forming polymers are generally derived from petrochemicals. For this reason, they are known as synthetic fibers. This would encompass Kevlar nylon as well as polyethylene terephthalate (PET) and polyethylene. Fibers made from natural polymers are not considered genuine synthetics and are known as recycled fibers. The latter group consists of viscose and cellulose acetate, as well as new developments such as chitosan, which is derived from the abundant substance chitin found in sea creatures. Despite most synthetic fibers on the market, it was the initial invention of regenerated cellulose that laid the foundation for many of the methods and processes used today to produce fibers using synthetic and natural raw materials.

One of the most significant advances fiber scientists have made is regenerable fibers. Regenerated fibers are made from natural sources without human interference. Many regenerated fibers are created from wood pulp such as viscose, lyocell rayon, and modal. These have been used as reinforcements in the manufacture of composite materials. In the current context, this approach shows more potential for sustainability and environmental impacts, such as recycling and reuse.

The main component of a macromolecule made of cellulose is glucose. The formula of the cellulose macromolecule is (C 6H 10O 5)n where n refers to the number of glucose molecules in the cellulose macromolecule and is known as the “degree of polymerization (DP)”. Cellulose A (insoluble in cold diluted NaOH) has a DP greater than 200, while b-cellulose (hemicelluloses that are soluble in cold diluted NaOH) has a DP less than 200. Wood pulp is the basis for cellulose production and then processed to improve the amount of a-cellulose. The amount of up to 99 percent can be achieved depending on the cleaning method. Regenerated fibers are manufactured by the viscose spinning method.

Manufacturing Process of Synthetic and Regenerated Fibers:

Synthetic fiber is made up of various types of polymers. It is not cultivated as a natural fiber. Regenerated fiber is made in the process of dissolving the cellulose region of plant fibers into chemical compounds and then transforming it into fiber. Synthetic fibers used in textiles they are manufactured using the same basic processes. In this post, I will review the manufacturing process of synthetic and regenerated fibers using a diagram.

In general, a liquid polymer is passed through a series of small holes to create an initial shape. The liquid is then stimulated to solidify by cooling, chemical, or thermodynamic processes, resulting in the formation of a solid filament. There are four ways to spin filaments from manufactured fibers including dry and wet melting as well as gel spinning.

Melt yarn:

Fusion spinning is the process of fusion. polymer chips are heated in a large hopper and then washed through metering pumps before reaching the spinneret. The filaments are then passed through cold air, which hardens them before they are pulled and wound onto spools. Thermoplastic fibers are manufactured by melt spinning. Polyester, nylon and liquid aromatic polymer are made by melt spinning. They are first heated to their melting temperature and then spun through spinnerets to create a continuous fiber, followed by drawing, cooling and winding. That is the method that is carried out.

Melt spinning has the advantage of not using solvents and using the polymer itself. Polymer melts are generally extremely viscous and cause the exudate to swell as it exits the rotating orifice. The swelling of the exudate is caused by elastic materials that recover from compression after leaving the orifice. The main consequences of exudate swelling are that the filaments always differ in cross-sectional shape.

of a complicated orifice, which means that extremely complex fiber geometries might not be feasible in fusion.

wet spin:

Resolution spinning is generally used when smooth spinning cannot be achieved for non-thermoplastic and temperature-sensitive polymers. In this arrangement, the polymer chains dissolve in a suitable solvent, forming a viscous liquid. Typically, solution concentrations can range from 1% to 25% depending on chain length, as well as solvent system and spin pack design. After dissolving in solution, the chains are usually free to unravel and move one by one. There are three types of wet spinning and the basic scheme of each is shown in the figure. In all variations, the polymer solution moves through a spinneret before the filaments are developed by precipitation or evaporation. Wet-dry spinning is when the solvent is volatile enough to evaporate quickly, leaving a slowly solidifying filament with only a little solvent left. When spinning with air gap and coagulation, the spinneret is submerged or suspended above the spin bath and the solvent is removed from the filament with the coagulating or non-solvent system. The filaments are then hardened and go through several drying and washing steps before being wound. Since the rate of diffusion of coagulant and solvent is crucial, wet spinning is generally slower than melt spinning.

Continuous filament spinning allows additives to be added to fibers in the course of creation. For example, yarn-dyed fibers are produced by batch addition of colors. This reduces the need to dye fibers and is necessary for difficult dyed fibers such as polypropylene. However, the color selection and minimum run size is often less extensive.

Another aspect of synthetic fibers is that the production process can often lock tension and stress the fibers at the molecular level. When fibers are heated for dyeing, bonding, or finishing, the fibers can expand as tension is relaxed, resulting in yarn shrinkage and material shrinkage in one direction, if not both. Residual shrinkage is usually removed by a finishing procedure called a heat setting process. In this process, the fabric is cleaned and then allowed to shrink according to a predetermined process using high-temperature ovens that eliminate up to 20 percent of shrinkage. This is an expensive process, however the final product is expected to be thermally stable during subsequent steps.

Dry spin:

The polymer solution passes through metering pumps. After passing through the spinneret, the filaments pass through hot air which evaporates the solvent and then dries the filament. After drying, the filament is pulled and wound on bobbins. Dry spinning produces polymeric fibers by removing the solution. It is a simple process. In this case, a solvent is needed, as well as the solvent recovery plant. There is no washing in this procedure. This process can be used to make triacetate, acrylic, modacrylic, PBI, Spandex, and Vinyan acetate.

Gel spin:

The process is called wet-dry spinning because the filaments are cooled by moving through cold air before being dragged into a water bath to cool them down. This is a specific procedure used to achieve strong or specific fiber characteristics. The polymer forms as a liquid or gel, in contrast to the other three processes which result in the polymer chains joining together in the form of liquid crystals, resulting in extremely powerful interchain forces. The polymer chains that make up the fibers have a very high degree of orientation, which greatly improves their tensile strength. This method applies to reinforced fiber and polyethylene.

Leave a Reply

Your email address will not be published.