Chemical fibers are made from natural or synthetic polymers as raw materials, and processed through chemical methods and mechanical processing.
1. Classification by Raw material Source
Chemical fibers can be divided into two major categories: regenerated fibers and synthetic fibers.
Regenerated fibers, also known as man-made fibers, are fibers made from natural polymers or fiber raw materials that have lost their textile processing value through a series of chemical treatments and mechanical processing. The chemical composition of the fibers is basically the same as that of the original polymer. This includes regenerated cellulose fibers (such as viscose fibers and cuprammonium fibers), regenerated protein fibers (such as soy protein fibers and peanut protein fibers), regenerated inorganic fibers (such as glass fibers and metal fibers), and regenerated organic fibers (such as chitosan fibers and alginic acid fibers).
Synthetic fibers are fibers made from natural low molecular weight compounds such as petroleum, coal, limestone, natural gas, salt, air, water, and certain agricultural by-products as raw materials, through chemical synthesis and processing. Common synthetic fibers include seven major categories: polyester fibers, polyamide fibers (nylon), polyacrylonitrile fibers (acrylic), polyvinyl alcohol formaldehyde fibers (vinylon), polypropylene fibers (polypropylene), polyvinyl chloride fibers (chlorine fibers), and polyurethane elastic fibers (spandex) and so on.
2. Classification by Morphological Structure
According to the morphological structure characteristics of chemical fibers, they are usually divided into two major categories: continuous filaments and staple fibers.
2.1 Continuous Filaments
In the manufacturing process of chemical fibers, the spinning fluid (melt or solution) is processed through spinning and post-processing to obtain fibers with a length of thousands of meters, called chemical fiber filaments. Chemical fiber filaments can be divided into monofilaments, multifilaments, twisted filaments, combined twisted filaments, curtain filaments, and textured filaments.
Monofilament: A single, continuous fiber with a very long length.
Multifilament: A yarn composed of two or more monofilaments combined together. Chemical fiber multifilaments generally consist of 8 to 100 or fewer single fibers.
Twisted filament: A multifilament twisted into a twisted filament.
Combined twisted filament: Two or more twisted filaments are combined and twisted to form a combined twisted filament.
Curtain filament: A yarn composed of more than a hundred to several hundred single fibers, used to make tire curtain fabric.
Textured filament: Chemical fiber raw filaments are processed to have a curled, spiral, or looped appearance, resulting in a fluffy, stretchable filament.
2.2 Short Fiber
Chemical fiber products are cut into lengths of several centimeters to tens of centimeters, and these lengths of fibers are called short fibers. According to the cutting length, short fibers can be divided into cotton type, wool type, and medium-length type. Cotton-type fibers have a length of 30-40mm and a linear density of about 1.67 dtex. The fibers are finer and similar to cotton. Wool-type fibers have a length of 70-150mm and a linear density of 3.3-7.7 dtex. The fibers are coarser and similar to wool. Medium-length fibers have a length of 51-65mm and a linear density of 2.2-3.3 dtex, which is between cotton-type and wool-type fibers.
3. Classification by Fiber Manufacturing Method
Chemical fibers can be divided into two categories according to the basic manufacturing methods: melt-spun fibers and solution-spun fibers (i.e., dry-spun fibers and wet-spun fibers).
Melt spinning is a method in which the polymer melt is extruded from the spinneret hole, and the melt filaments solidify into fibers in the surrounding air (or water). Polyester Chips are the raw material of melt spinning. Dry spinning is a method in which the polymer concentrated solution is extruded from the spinneret hole, forming filaments that solidify into fibers as the solvent evaporates rapidly in the heat medium. Wet spinning is a method in which the polymer concentrated solution is extruded from the spinneret hole and solidified into fibers in the coagulation bath.
4. Classification by Composition of Single Fibers
Single fibers are classified into single-component fibers and multi-component fibers according to their composition. Fibers made of the same polymer are called single-component fibers. Most conventional fibers are single-component fibers, such as polyester. Fibers made of two or more polymers are called multi-component fibers, such as acrylic fibers. The fibers are called composite fibers if the components are arranged regularly along the fiber axis and form continuous interfaces. If the components are randomly dispersed or mixed more evenly, the fibers are called blended fibers.
5. Classification by Fiber Differences
This category of chemical fibers mainly includes three types: differential fibers, functional fibers, and high-performance fibers.
Differential fibers refer to chemical fibers that are different from conventional fibers due to chemical or physical changes, such as shaped fibers, composite fibers, ultrafine fibers, easy-dyeing fibers, flame-retardant fibers, hydrophilic synthetic fibers, colored fibers, and anti-pilling fibers. Hubei Decon helps customers customize the raw material (Polymer) of various differential fibers.
Functional fibers refer to fibers that have some special functions in addition to their existing properties, such as conductive fibers, optical fibers, ion-exchange fibers, ceramic particle-containing fibers, temperature-regulating insulation fibers, radiation-resistant fibers, bioactive fibers, biodegradable fibers, negative ion-producing fibers, and antibacterial and deodorizing fibers.
High-performance fibers refer to special fibers with a strength of 17.7 cN/dtex and a modulus of 441.5 cN/dtex or higher, such as carbon fibers, aromatic polyamide fibers, polybenzimidazole fibers, polyphenylene sulfide fibers, and ultra-high molecular weight polyethylene fibers.