Pairing Principle for Polymer Raw Materials of Bicomponent Fibers

Pairing Principle for Polymer Raw Materials of Bicomponent Fibers

 

When spinning bi-component fibers, it's crucial that the melt viscosities of the two paired polymers are closely matched and that they demonstrate good compatibility. Otherwise, peeling during the spinning process may occur, complicating the achievement of the desired results. Furthermore, the two components should exhibit a significant difference in thermal shrinkage to create a distinct spiral three-dimensional curling structure.

 

Some fibers bend significantly right after they exit the spinneret, which makes them likely to stick to the surface of the spinneret. This can disrupt spinning stability and cause a misalignment between the parallel fiber interface layer and the intended shape of the filament. Pairing of this is not ideal.

 

Under the spinning process conditions, the two components demonstrate good compatibility. After the formation of the fibers, the sheath-core structure of the two components integrates smoothly, with no noticeable boundary or separation between the sheath and the core. To achieve this seamless integration, the viscosities of the two component melts should be as similar as possible. A significant difference in melt viscosity can cause issues, such as the formation of melt elbows during the extrusion of the polymer from the spinneret.

 

When spinning sheath-core fibers, the spinnability requirements are generally lower than those for side-by-side fibers. However, the melting points of the two polymer components should not differ significantly. The low-melting-point sheath can be used for thermal bonding. Common material pairings include polyethylene (PE) with polypropylene (PP), polyethylene (PE) with polyethylene terephthalate (PET), and copolyester (Co-PET) with polyethylene terephthalate (PET).

 

Both components must maintain the same drawing speed, which requires that the melts of both components possess good tensile strength. This strength is crucial for enduring higher drawing speeds and forces, thus preventing filament breakage in either component during the drawing process.

 

The polymers of both components need to exhibit good thermal stability to prevent changes in morphology (such as curling) and properties during temperature fluctuations, after treatment, or storage.

 

Some paired fibers have varying qualities in feel, and production costs, such as recyclability, must be considered. If the cost is too high, it will lack practicality.

 

It is important to consider the requirements of the subsequent processes. For example, side-by-side fibers are easier to separate when they are paired with PET/PA6, but they become difficult to separate when paired with PET/PP. Additionally, in the case of sheath-core fibers combined with PET/PE, the sheath made of PE can be easily removed. This is why these pairing schemes are not commonly used.

 

When PP (polypropylene) and CoPP (copolymer polypropylene) are combined, hot air through consolidation cannot be used because both components are essentially the same polymer and have similar melting points. In this scenario, only thermal calendering is applicable. However, this product shows better recyclability. On the other hand, if the two component polymers have significantly different performance characteristics, the recyclability of the resulting product is often poor.

 

When spinning eccentric fibers, the requirements for spinnability are slightly more stringent than those for concentric fibers. It is crucial for the melts of the two components to have similar viscosities during the spinning process. This consistency helps prevent the formation of elbows when the melt is extruded from the spinneret, which can impact the stability of the spinning process.

 

The unique composite fiber made from two distinct polymers creates three-dimensional spiral curls, resulting in a fluffier texture for the non-woven fabric.

 

The selection of polymer raw materials for the sheath layer of sheath-core fibers significantly influences the consolidation method employed for nonwoven fiber webs. For example, when low-density polyethylene (LDPE) or high-density polyethylene (HDPE) is used as the sheath layer alongside polypropylene (PP), it shows enhanced performance during low-temperature processing. This improvement enables the use of hot air consolidation methods.

 

When CoPP is used as the outer layer in combination with polypropylene (PP), hot rolling consolidation can be employed. This process results in a non-woven fabric product with enhanced strength. On the other hand, when high-density polyethylene (HDPE), as sheath part, is paired with polyester (PET), hot air consolidation can be used. This technique is effective because of the significant difference in melting points between the two components, which allows the non-woven fabric product to achieve better heat resistance and increased fluffiness.

 

When PP, as the sheath, is paired with PET, ultrasonic consolidation can improve the fluffiness of the nonwoven product.

 

Bicomponent fibers are available in various structures and cross-sectional shapes, featuring different proportions of their two components. This variety enables bicomponent fibers to display unique characteristics that single-component fibers lack. Bicomponent production lines provide greater flexibility and play a crucial role in the development of spunbond nonwovens, offering companies innovative methods to achieve differentiated production. 

Pairing Principle for Polymer Raw Materials of Bicomponent Fibers

 

When spinning bi-component fibers, it's crucial that the melt viscosities of the two paired polymers are closely matched and that they demonstrate good compatibility. Otherwise, peeling during the spinning process may occur, complicating the achievement of the desired results. Furthermore, the two components should exhibit a significant difference in thermal shrinkage to create a distinct spiral three-dimensional curling structure.

 

Some fibers bend significantly right after they exit the spinneret, which makes them likely to stick to the surface of the spinneret. This can disrupt spinning stability and cause a misalignment between the parallel fiber interface layer and the intended shape of the filament. Pairing of this is not ideal.

 

Under the spinning process conditions, the two components demonstrate good compatibility. After the formation of the fibers, the sheath-core structure of the two components integrates smoothly, with no noticeable boundary or separation between the sheath and the core. To achieve this seamless integration, the viscosities of the two component melts should be as similar as possible. A significant difference in melt viscosity can cause issues, such as the formation of melt elbows during the extrusion of the polymer from the spinneret.

 

When spinning sheath-core fibers, the spinnability requirements are generally lower than those for side-by-side fibers. However, the melting points of the two polymer components should not differ significantly. The low-melting-point sheath can be used for thermal bonding. Common material pairings include polyethylene (PE) with polypropylene (PP), polyethylene (PE) with polyethylene terephthalate (PET), and copolyester (Co-PET) with polyethylene terephthalate (PET).

 

Both components must maintain the same drawing speed, which requires that the melts of both components possess good tensile strength. This strength is crucial for enduring higher drawing speeds and forces, thus preventing filament breakage in either component during the drawing process.

 

The polymers of both components need to exhibit good thermal stability to prevent changes in morphology (such as curling) and properties during temperature fluctuations, after treatment, or storage.

 

Some paired fibers have varying qualities in feel, and production costs, such as recyclability, must be considered. If the cost is too high, it will lack practicality.

 

It is important to consider the requirements of the subsequent processes. For example, side-by-side fibers are easier to separate when they are paired with PET/PA6, but they become difficult to separate when paired with PET/PP. Additionally, in the case of sheath-core fibers combined with PET/PE, the sheath made of PE can be easily removed. This is why these pairing schemes are not commonly used.

 

When PP (polypropylene) and CoPP (copolymer polypropylene) are combined, hot air through consolidation cannot be used because both components are essentially the same polymer and have similar melting points. In this scenario, only thermal calendering is applicable. However, this product shows better recyclability. On the other hand, if the two component polymers have significantly different performance characteristics, the recyclability of the resulting product is often poor.

 

When spinning eccentric fibers, the requirements for spinnability are slightly more stringent than those for concentric fibers. It is crucial for the melts of the two components to have similar viscosities during the spinning process. This consistency helps prevent the formation of elbows when the melt is extruded from the spinneret, which can impact the stability of the spinning process.

 

The unique composite fiber made from two distinct polymers creates three-dimensional spiral curls, resulting in a fluffier texture for the non-woven fabric.

 

The selection of polymer raw materials for the sheath layer of sheath-core fibers significantly influences the consolidation method employed for nonwoven fiber webs. For example, when low-density polyethylene (LDPE) or high-density polyethylene (HDPE) is used as the sheath layer alongside polypropylene (PP), it shows enhanced performance during low-temperature processing. This improvement enables the use of hot air consolidation methods.

 

When CoPP is used as the outer layer in combination with polypropylene (PP), hot rolling consolidation can be employed. This process results in a non-woven fabric product with enhanced strength. On the other hand, when high-density polyethylene (HDPE), as sheath part, is paired with polyester (PET), hot air consolidation can be used. This technique is effective because of the significant difference in melting points between the two components, which allows the non-woven fabric product to achieve better heat resistance and increased fluffiness.

 

When PP, as the sheath, is paired with PET, ultrasonic consolidation can improve the fluffiness of the nonwoven product.

 

Bicomponent fibers are available in various structures and cross-sectional shapes, featuring different proportions of their two components. This variety enables bicomponent fibers to display unique characteristics that single-component fibers lack. Bicomponent production lines provide greater flexibility and play a crucial role in the development of spunbond nonwovens, offering companies innovative methods to achieve differentiated production.