Polymer Spinning Processes of Filament Yarns

Polymer Spinning Processes :

There are a number of spinning processes.

Wet spinning: 

Among the four processes of chemical spinning, the oldest is wet spinning, as shown in Figure 1. This method is used for polymers that need to be dissolved in a solvent before cutting. The spinning solution is pumped though the spinneret. The spinneret is immersed in a coagulating chemical bath, whereby the polymer dissolves its solvent during spinning and then solidifies as it exits through the spinneret hole. (The spinning process derives its name from the use of this 'wet' bath.) Acrylic fibers, rayon fibers, aramid fibers, modacrylic fibers and spandex fibers are all produced by the wet spinning process.

Polymer Spinning Processes : There are a number of spinning processes. Wet spinning: Among the four processes of chemical spinning, the oldest is wet spinning, as shown in Figure 1. This method is used for polymers that need to be dissolved in a solvent before cutting. The spinning solution is pumped though the spinneret. The spinneret is immersed in a coagulating chemical bath, whereby the polymer dissolves its solvent during spinning and then solidifies as it exits through the spinneret hole. (The spinning process derives its name from the use of this 'wet' bath.) Acrylic fibers, rayon fibers, aramid fibers, modacrylic fibers and spandex fibers are all produced by the wet spinning process. Figure 1 Dry Spinning: Dry spinning is used for polymers that need to be dissolved in a solvent. However, solidification in this method is obtained by evaporation of the solvent. After the polymer is dissolved in a volatile solvent, the solution is pumped through a spinneret. As the spinning solution passes through the spinnet, air or inert gas is used to evaporate the solvent from the solvent to form fibers through solidification. This results in stiffness of the fibers, which can then be collected and wound on a take-up wheel. The fibers are drawn to provide orientation of the macromolecular polymer chains along the fiber axis. This technique is used only for polymers that cannot be wet-cut due to safety and environmental concerns related to solvent handling. Dry spinning can be used to produce acetate fiber, triacetate fiber, acrylic fiber, modacrylic fiber, PBI, spandex fiber and vion. The process flow of dry spinning is shown in Figure 2. Figure 2 Melt spinning: In this process, the thermoplastic fiber-forming polymer of the fiber-forming material is melted and then extruded through a spinneret. The molten fibrous material is cooled and the solid fibers are collected in a take-up wheel. The fibers expand in the melt and solid state, which facilitates the orientation of the polymer chains along the fiber axis. Meltspun fibers can be extruded through a spinneret in a variety of cross-sectional shapes, including circular, trilobal, pentagonal, and octagonal, depending on the spinneret's orifice design. The cross-sectional or anatomical properties of fibers are responsible for some of the characteristic physical properties of fibers. For example, trilobal-shaped fibers are able to reflect more light, giving the fabric a luster. The pentagonal and hollow fibers are soil and dirt resistant and are used in making carpets and rugs. Octagonal shaped fibers offer glossy effects, while hollow fibers trap air, creating better insulation. The most popular fiber-forming polymers such as polyethylene terephthalate and nylon 6-6 have high volume melts. Nylon fibers, olefin fibers, polyester fibers, saran fibers and some other thermoplastic synthetic fibers are produced by melt spinning. Gel spinning: Gel spinning is also known as dry-jet-wet spinning, because the filaments are first passed through dry air and then further cooled in a liquid bath (wet). Gel spinning is the most widely used method to produce very strong fibers with special properties. The polymer forming the fiber is partially in a liquid or 'gel' state, which holds the polymer molecular chains bound together to some extent at various points in the liquid crystalline form. This bonding creates strong intermolecular forces within the fiber, which increases its tensile strength. The macromolecular polymer chains within the fibers also have a high degree of orientation, which further increases its strength. Strength is further enhanced by emerging filaments with an unusually high degree of orientation relative to each other. High-strength polyethylene and aramid fibers are currently manufactured by this process in industry. The process flow of gel spinning is shown in Figure 3. Figure 3 Regardless of the extrusion or spinning process used for chemical spinning of fibers, the fibers are ultimately drawn to increase both their strength and molecular orientation. This is done either while the polymer is still in the process of solidification or after it has completely cooled. The drawing forces the molecular chains to come together and orient them along the fiber axis, resulting in a considerably stronger yarn. Man-made filament yarns can be further divided into the following four subgroups depending on their physical structure: plain, textured, bi-component, and film (tape or split) yarns.
Figure 1


Dry Spinning: 

Dry spinning is used for polymers that need to be dissolved in a solvent. However, solidification in this method is obtained by evaporation of the solvent. After the polymer is dissolved in a volatile solvent, the solution is pumped through a spinneret. As the spinning solution passes through the spinnet, air or inert gas is used to evaporate the solvent from the solvent to form fibers through solidification. This results in stiffness of the fibers, which can then be collected and wound on a take-up wheel. The fibers are drawn to provide orientation of the macromolecular polymer chains along the fiber axis. This technique is used only for polymers that cannot be wet-cut due to safety and environmental concerns related to solvent handling. Dry spinning can be used to produce acetate fiber, triacetate fiber, acrylic fiber, modacrylic fiber, PBI, spandex fiber and vion. The process flow of dry spinning is shown in Figure 2.

Polymer Spinning Processes : There are a number of spinning processes. Wet spinning: Among the four processes of chemical spinning, the oldest is wet spinning, as shown in Figure 1. This method is used for polymers that need to be dissolved in a solvent before cutting. The spinning solution is pumped though the spinneret. The spinneret is immersed in a coagulating chemical bath, whereby the polymer dissolves its solvent during spinning and then solidifies as it exits through the spinneret hole. (The spinning process derives its name from the use of this 'wet' bath.) Acrylic fibers, rayon fibers, aramid fibers, modacrylic fibers and spandex fibers are all produced by the wet spinning process. Figure 1 Dry Spinning: Dry spinning is used for polymers that need to be dissolved in a solvent. However, solidification in this method is obtained by evaporation of the solvent. After the polymer is dissolved in a volatile solvent, the solution is pumped through a spinneret. As the spinning solution passes through the spinnet, air or inert gas is used to evaporate the solvent from the solvent to form fibers through solidification. This results in stiffness of the fibers, which can then be collected and wound on a take-up wheel. The fibers are drawn to provide orientation of the macromolecular polymer chains along the fiber axis. This technique is used only for polymers that cannot be wet-cut due to safety and environmental concerns related to solvent handling. Dry spinning can be used to produce acetate fiber, triacetate fiber, acrylic fiber, modacrylic fiber, PBI, spandex fiber and vion. The process flow of dry spinning is shown in Figure 2. Figure 2 Melt spinning: In this process, the thermoplastic fiber-forming polymer of the fiber-forming material is melted and then extruded through a spinneret. The molten fibrous material is cooled and the solid fibers are collected in a take-up wheel. The fibers expand in the melt and solid state, which facilitates the orientation of the polymer chains along the fiber axis. Meltspun fibers can be extruded through a spinneret in a variety of cross-sectional shapes, including circular, trilobal, pentagonal, and octagonal, depending on the spinneret's orifice design. The cross-sectional or anatomical properties of fibers are responsible for some of the characteristic physical properties of fibers. For example, trilobal-shaped fibers are able to reflect more light, giving the fabric a luster. The pentagonal and hollow fibers are soil and dirt resistant and are used in making carpets and rugs. Octagonal shaped fibers offer glossy effects, while hollow fibers trap air, creating better insulation. The most popular fiber-forming polymers such as polyethylene terephthalate and nylon 6-6 have high volume melts. Nylon fibers, olefin fibers, polyester fibers, saran fibers and some other thermoplastic synthetic fibers are produced by melt spinning. Gel spinning: Gel spinning is also known as dry-jet-wet spinning, because the filaments are first passed through dry air and then further cooled in a liquid bath (wet). Gel spinning is the most widely used method to produce very strong fibers with special properties. The polymer forming the fiber is partially in a liquid or 'gel' state, which holds the polymer molecular chains bound together to some extent at various points in the liquid crystalline form. This bonding creates strong intermolecular forces within the fiber, which increases its tensile strength. The macromolecular polymer chains within the fibers also have a high degree of orientation, which further increases its strength. Strength is further enhanced by emerging filaments with an unusually high degree of orientation relative to each other. High-strength polyethylene and aramid fibers are currently manufactured by this process in industry. The process flow of gel spinning is shown in Figure 3. Figure 3 Regardless of the extrusion or spinning process used for chemical spinning of fibers, the fibers are ultimately drawn to increase both their strength and molecular orientation. This is done either while the polymer is still in the process of solidification or after it has completely cooled. The drawing forces the molecular chains to come together and orient them along the fiber axis, resulting in a considerably stronger yarn. Man-made filament yarns can be further divided into the following four subgroups depending on their physical structure: plain, textured, bi-component, and film (tape or split) yarns.
Figure 2


Melt spinning: 

In this process, the thermoplastic fiber-forming polymer of the fiber-forming material is melted and then extruded through a spinneret. The molten fibrous material is cooled and the solid fibers are collected in a take-up wheel. The fibers expand in the melt and solid state, which facilitates the orientation of the polymer chains along the fiber axis. Meltspun fibers can be extruded through a spinneret in a variety of cross-sectional shapes, including circular, trilobal, pentagonal, and octagonal, depending on the spinneret's orifice design. The cross-sectional or anatomical properties of fibers are responsible for some of the characteristic physical properties of fibers. For example, trilobal-shaped fibers are able to reflect more light, giving the fabric a luster. The pentagonal and hollow fibers are soil and dirt resistant and are used in making carpets and rugs. Octagonal shaped fibers offer glossy effects, while hollow fibers trap air, creating better insulation. The most popular fiber-forming polymers such as polyethylene terephthalate and nylon 6-6 have high volume melts. Nylon fibers, olefin fibers, polyester fibers, saran fibers and some other thermoplastic synthetic fibers are produced by melt spinning.


Gel spinning: 

Gel spinning is also known as dry-jet-wet spinning, because the filaments are first passed through dry air and then further cooled in a liquid bath (wet). Gel spinning is the most widely used method to produce very strong fibers with special properties. The polymer forming the fiber is partially in a liquid or 'gel' state, which holds the polymer molecular chains bound together to some extent at various points in the liquid crystalline form. This bonding creates strong intermolecular forces within the fiber, which increases its tensile strength. The macromolecular polymer chains within the fibers also have a high degree of orientation, which further increases its strength. Strength is further enhanced by emerging filaments with an unusually high degree of orientation relative to each other. High-strength polyethylene and aramid fibers are currently manufactured by this process in industry. The process flow of gel spinning is shown in Figure 3.

Polymer Spinning Processes : There are a number of spinning processes. Wet spinning: Among the four processes of chemical spinning, the oldest is wet spinning, as shown in Figure 1. This method is used for polymers that need to be dissolved in a solvent before cutting. The spinning solution is pumped though the spinneret. The spinneret is immersed in a coagulating chemical bath, whereby the polymer dissolves its solvent during spinning and then solidifies as it exits through the spinneret hole. (The spinning process derives its name from the use of this 'wet' bath.) Acrylic fibers, rayon fibers, aramid fibers, modacrylic fibers and spandex fibers are all produced by the wet spinning process. Figure 1 Dry Spinning: Dry spinning is used for polymers that need to be dissolved in a solvent. However, solidification in this method is obtained by evaporation of the solvent. After the polymer is dissolved in a volatile solvent, the solution is pumped through a spinneret. As the spinning solution passes through the spinnet, air or inert gas is used to evaporate the solvent from the solvent to form fibers through solidification. This results in stiffness of the fibers, which can then be collected and wound on a take-up wheel. The fibers are drawn to provide orientation of the macromolecular polymer chains along the fiber axis. This technique is used only for polymers that cannot be wet-cut due to safety and environmental concerns related to solvent handling. Dry spinning can be used to produce acetate fiber, triacetate fiber, acrylic fiber, modacrylic fiber, PBI, spandex fiber and vion. The process flow of dry spinning is shown in Figure 2. Figure 2 Melt spinning: In this process, the thermoplastic fiber-forming polymer of the fiber-forming material is melted and then extruded through a spinneret. The molten fibrous material is cooled and the solid fibers are collected in a take-up wheel. The fibers expand in the melt and solid state, which facilitates the orientation of the polymer chains along the fiber axis. Meltspun fibers can be extruded through a spinneret in a variety of cross-sectional shapes, including circular, trilobal, pentagonal, and octagonal, depending on the spinneret's orifice design. The cross-sectional or anatomical properties of fibers are responsible for some of the characteristic physical properties of fibers. For example, trilobal-shaped fibers are able to reflect more light, giving the fabric a luster. The pentagonal and hollow fibers are soil and dirt resistant and are used in making carpets and rugs. Octagonal shaped fibers offer glossy effects, while hollow fibers trap air, creating better insulation. The most popular fiber-forming polymers such as polyethylene terephthalate and nylon 6-6 have high volume melts. Nylon fibers, olefin fibers, polyester fibers, saran fibers and some other thermoplastic synthetic fibers are produced by melt spinning. Gel spinning: Gel spinning is also known as dry-jet-wet spinning, because the filaments are first passed through dry air and then further cooled in a liquid bath (wet). Gel spinning is the most widely used method to produce very strong fibers with special properties. The polymer forming the fiber is partially in a liquid or 'gel' state, which holds the polymer molecular chains bound together to some extent at various points in the liquid crystalline form. This bonding creates strong intermolecular forces within the fiber, which increases its tensile strength. The macromolecular polymer chains within the fibers also have a high degree of orientation, which further increases its strength. Strength is further enhanced by emerging filaments with an unusually high degree of orientation relative to each other. High-strength polyethylene and aramid fibers are currently manufactured by this process in industry. The process flow of gel spinning is shown in Figure 3. Figure 3 Regardless of the extrusion or spinning process used for chemical spinning of fibers, the fibers are ultimately drawn to increase both their strength and molecular orientation. This is done either while the polymer is still in the process of solidification or after it has completely cooled. The drawing forces the molecular chains to come together and orient them along the fiber axis, resulting in a considerably stronger yarn. Man-made filament yarns can be further divided into the following four subgroups depending on their physical structure: plain, textured, bi-component, and film (tape or split) yarns.
Figure 3

Regardless of the extrusion or spinning process used for chemical spinning of fibers, the fibers are ultimately drawn to increase both their strength and molecular orientation. This is done either while the polymer is still in the process of solidification or after it has completely cooled.

The drawing forces the molecular chains to come together and orient them along the fiber axis, resulting in a considerably stronger yarn. Man-made filament yarns can be further divided into the following four subgroups depending on their physical structure: plain, textured, bi-component, and film (tape or split) yarns.


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