How is microfiber made?
Microfibers can be manufactured using various methods. All the three basic types of spinning process namely melt spinning, wet spinning and dry spinning can be used to manufacture microfiber. Lets see what are all the methods to produce microfiber:
• Dissolved type:
To produce dissolve types of microfibers, bi-component fibers with different types of polymers are used. Bi-component filaments which are comparatively thicker than normal filament fibers that contain different types of incompatible polymers are spun, and then the fabric is made using them.. After that the fabric is treated chemically using solvents, the chemicals dissolve on components in the fabrics and hence the other component remains as the microfiber. This method is used to manufacture polyester and nylon microfibers.
• Split type:
In the split type method of manufacturing microfiber, the bi-component filaments containing two types of polymers are first treated physically or chemically and then are split into different types of filaments. This is mainly because it is much easier to split the segment in filament from itself than in the fabrics. Splittable bi-component filament spinning method is used for manufacturing polyamides/polyester and polyester/polyolefins microfibers.
• Direct spun type:
Direct spun types of microfiber are directly manufactured by the melt spinning process. For producing microfiber using this method highly selected polymerization, polymer, spinning conditions and drawing conditions are required.
When at the given temperature polymers have similar dynamic viscosities, the polymer with the lower dynamic viscosity permits the spinning of finer fibres. Due to this lower spin-line tension is generated during the process of spinning polymers. The increased takeup velocity combined with the spin line stress level results in attaining the minimum fineness into the fibers.
• Super-drawing technique:
No molecular orientation is involved in the super drawing technique of manufacturing microfibers. Achieving higher drawing ratios can produce staple fibre with a linear density of less than 0.5 dtex. This is the principle used in the super drawing technique. At a minimum crystallizing temperature and at specially selected drawing conditions, including the temperature range and the type of heating, the yarns can be stretched as much as 10–75 times much beyond their conventional draw ratios which are around 3–6 times.
• Sheath-core spinning method:
In the sheath core spinning method of producing microfiber, under specified conditions two different polymers are mixed, melted and mix-annealed. Hence in the sheath core spinning method, the conjugate fibre consisting of a concentric circular sheath and a core is manufactured. The sheath portion is removed to form ultra-fine fibres.