Filament, staple fiber, composite, special-shaped, superfine fiber... can you distinguish it clearly?

2021/04/09

Guid:Classification and introduction of 12 kinds of synthetic fibers








Filament, staple fiber, composite, special-shaped, superfine fiber... can you distinguish it clearly?
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Filament, staple fiber, composite, special-shaped, superfine fiber... can you distinguish it clearly?

 synthetic fibers

 

#1. Filament

 

In the manufacturing process of synthetic fibers, the spinning fluid (melt or solution) undergoes spinning forming and post-processing procedures, and the resulting fibers with a length of kilometers are called filaments. The filament includes monofilament, multifilament and cord yarn.

 

1.1 Monofilament

continuous single fiber

Originally refers to a continuous single fiber spun with a single-hole spinneret, but in practical applications it often includes a few-hole filament composed of 3-6 single fibers spun from a 3-6-hole spinneret. Thicker synthetic fiber monofilaments (0.08-2mm in diameter) are called bristles, which are used to make ropes, brushes, daily net bags, fishing nets or industrial filter cloth; thinner polyamide monofilaments are used to make Transparent women's socks or other high-end knitwear.

 

1.2 Multifilament

Multifilament

A thread composed of dozens of single fibers. The multifilament of chemical fiber is generally composed of 8-100 single fibers. Absolutely

Most clothing fabrics are woven with multifilaments, because multifilaments composed of multiple filaments are more flexible than single filaments of the same diameter.

 

1.3 Cord yarn

Cord yarn

A thread used to make tire cord fabric composed of more than one hundred to several hundred single fibers, commonly known as cord yarn.

 

#2. Short fiber

 

Chemical fiber products are cut into lengths of several centimeters to ten centimeters, and fibers of this length are called short fibers. According to cut off

Depending on the length, short fibers can be divided into cotton short fibers, wool short fibers, and medium-length short fibers.

 

2.1 Cotton type short fiber

 

The length is 25~38mm, the fiber is relatively thin (the linear density is 1.3~1.7dtex), similar to cotton fiber, mainly used for blending with cotton fiber, such as cotton polyester staple fiber and cotton fiber blending, the resulting fabric Called "polyester cotton" fabric.

 

2.2 Hair type short fiber

The length is 70~150mm, the fiber is relatively thick (linear density 3.3~7.7dtex), similar to wool, mainly used for blending with wool, such as wool-type polyester staple fiber and wool blending, the resulting fabric is called "wool polyester" "Fabric.

 

2.3 Medium short fiber

 

The length is 51~76mm, the fiber thickness is between cotton and wool type (linear density is 2.2~3.3dtex), mainly used for weaving medium and long fiber fabrics.

 

In addition to blending with natural fibers, short fibers can also be blended with short fibers of other chemical fibers. The resulting blended fabric has good comprehensive properties. In addition, short fibers can also be spun purely. In the current world chemical fiber production, the output of short fiber is higher than that of filament. According to fiber characteristics, some varieties (such as nylon) mainly produce filaments; some varieties (such as acrylic) mainly produce short fibers; and some varieties (such as polyester) have a relatively close ratio of the two.

 

#3. Thick and detailed wire

 

Thick and detailed silk is abbreviated as T&T silk. From its appearance, you can see the alternating thick and detailed parts, and after dyeing, you can see the alternating dark and light colors. Thick and minute yarns are made by uneven drafting technology after spinning forming. The difference in properties of the two parts of yarn produced can be controlled in production, and its distribution is irregular and present in a natural state.

 

The thick section of the thick fine yarn has low strength, large elongation at break, strong heat shrinkability, good dyeability, and easy alkali reduction processing. These characteristics can be fully utilized to develop unique textiles. The physical properties of the coarse detail wire are related to factors such as the diameter ratio of the coarse detail. General thick fine yarns have higher breaking elongation and boiling water shrinkage, as well as lower breaking strength and yield. Its strong shrinkage performance can make thick fine yarns mixed with other yarns into hetero-shrinkage mixed filament yarns. In addition, the thick sections of the thick and small yarns are easy to deform and have low strength, which should be paid attention to in the process of weaving, dyeing and finishing. The initial coarse detail yarns were round yarns. With the development of the production technology of coarse detail yarns, some special coarse detail yarns have appeared one after another, such as special-shaped coarse detail yarns, mixed fiber coarse and fine yarns, microporous coarse and fine yarns, and fine denier coarsening. Detailed silk, etc., they have a special feel and style, or have a special absorbency, and are mostly used to develop high-end fabrics.

 

#4. Textured yarn

Textured yarn includes all yarns and yarns that have undergone texturing, such as stretch yarn and bulked yarn.

 

4.1 Stretch yarn

 

That is, deformed filaments can be divided into two types: high-elastic yarns and low-elastic yarns. Elastic yarn has good stretchability and bulkiness, and its fabric is close to wool, silk or cotton in terms of thickness, weight, opacity, coverage and appearance characteristics. Polyester stretch yarn is mostly used for clothing, nylon stretch yarn is suitable for socks, and polypropylene stretch yarn is mostly used for household fabrics and carpets. The deformation methods mainly include false twisting method, air jet method, hot air jet method, stuffer box method and shaping method.

 

4.2 Bulk yarn

 

That is, using the thermoplasticity of the polymer compound, the two synthetic fiber tops with different shrinkage properties are mixed in proportion. After heat treatment, the high shrinkage top forces the low shrinkage top to curl, so that the mixed top has stretchability and bulkiness, and becomes similar. Textured yarn of wool. At present, acrylic fiber bulked yarn has the largest output, which is used to make knitted outerwear, underwear, woolen yarn, blankets and so on.

 

#5. Differential fiber

Differential fiber

Differential fiber is a loanword from Japan. It generally refers to a fiber material obtained by physical deformation or chemical modification on the basis of the original chemical fiber. It is obviously different from ordinary chemical fiber in terms of appearance or internal quality. Differentiated fibers not only improve and enhance the performance and style of chemical fibers, but also endow chemical fibers with new functions and characteristics, such as high water absorption, electrical conductivity, high shrinkage and dyeability. Because differentiated fibers are mainly used to improve the simulation effect, improve comfort and protection, they are mainly used to develop wool-like, linen-like, and silk-like clothing textiles, and part of them are used to develop paving textiles and industrial textiles.

 

#6. Shaped fiber

In synthetic fiber spinning and forming processing, fibers with non-circular cross-section or hollow fibers spun with special-shaped nozzle holes are called special-shaped cross-section fibers, or special-shaped fibers for short. At present, there are dozens of types of shaped fibers. About 50% of the polyester fibers, polyamide fibers and polyacrylonitrile fibers sold on the market are shaped fibers.

 Shaped fiber

The figure above shows the shapes of spinneret holes (top) and the cross-sectional shapes of the corresponding fibers (bottom).

 

It should be noted that the cross-section of fibers (such as viscose fiber and polyacrylonitrile fiber) obtained by wet spinning with circular spinneret holes is not a perfect circle, but may be zigzag, waist or dumbbell shape. Nevertheless, they cannot be called special-shaped fibers. Shaped fibers with different cross-sections have different properties, and their roles in textile development are also different. Compared with ordinary round fibers, special-shaped fibers have the following characteristics:

 

6.1 Gloss and feel

 

The gloss of the fiber is related to the cross-sectional shape of the fiber. Triangular cross-section wire and trilobal cross-section wire have shining luster, which improves the "aurora" phenomenon of round fibers. For example: the triangular cross-section of polyester fiber or polyamide fiber and other fiber blended fabric has a flashing effect, suitable for the development of silk-like fabrics, wool-like fabrics and a variety of velvet fabrics. The flat, ribbon-shaped, dumbbell-shaped cross-section synthetic fibers have the feel and luster of fibers such as hemp, antelope wool and rabbit hair. The five-lobed cross-section polyester filament has a luster similar to real silk, and at the same time, it has good anti-pilling, hand feeling and covering properties. Polygonal cross-section yarns have brilliance, strong covering power and soft hand feeling. They are mostly used to make textured yarns to make knitted fabrics and socks. The short fibers are used for blending to make a variety of wool-like fabrics and blanket products. The rectangular cross-section silk has a soft luster, which is close to the luster of silk and animal hair. The blended product of short fiber and cotton fiber has a woolen style, and blended with wool can obtain a shiny and unique fabric.

 

6.2 Mechanical properties, water absorption and dyeability

 

The rigidity of the shaped fiber is stronger, the resilience and coverage can also be improved, and the strength is slightly reduced. In addition, the shaped fiber has a larger surface area, enhanced water and steam transmission capacity, fast drying speed, and good dyeability.

 

6.3 Anti-pilling, bulkiness and air permeability

 

Fibers with flat cross-section shapes can significantly improve the pilling phenomenon, and the greater the flatness, the better the effect, such as polyester and polyamide flat cross-section fibers and wool blends Later, the fabric is generally not easy to pilling. Shaped fibers usually have good bulkiness, the fabric feels plump, has strong warmth retention, and because of the increase in pores, it has good air permeability. With the increase of cross-sectional irregularities, its bulkiness and air permeability are also improved.

 

6.4 The specificity of hollow fibers

 

Hollow fibers have excellent warmth retention and bulkiness. Some hollow fibers also have special uses, such as making reverse osmosis membranes, used for artificial kidneys, seawater desalination, sewage treatment, hard water softening, and solution concentration. Wait.

 

#7. Composite fiber

There are two or more immiscible polymers on the cross section of the fiber. Such chemical fibers are called composite fibers, or bicomponent fibers. Because the two or more components contained in this fiber complement each other, the performance of composite fiber is usually better than that of conventional synthetic fiber, and it has many uses.

 

There are many types of composite fibers, which can be divided into two categories according to their shapes, namely, double-layer type and multi-layer type. Double-layer type includes side-by-side type and skin-core type. Multi-layer type includes side-by-side multilayer type, radial type, multi-core type, wood grain type, embedded type, sea-island type and split type.

 composite fibers

 The cross-sectional shapes of several composite fibers are shown in the figure.

 

The main characteristic of side-by-side composite fiber is high crimping, which can make the fabric fluffy, soft, warm-keeping performance and wool-like style. It is mainly used in bulked wool, knitted fabrics, hosiery and blanket products. The skin-core composite fiber is divided into partial skin-core type and concentric skin-core type. The former has three-dimensional crimp, but the crimp is not as good as the side-by-side composite fiber.

 

According to the properties of different polymers and their distribution positions on the fiber cross section, many composite fibers with different properties and uses can be obtained.

 

For example: using side-by-side composite and partial skin-core composite (see Figures (1), (2), (4)), due to the different thermoplasticity of the two polymers or asymmetric distribution on the fiber cross section, in the post-treatment process The shrinkage is poor, so that the fiber produces spiral crimps, which can be made into composite fibers with wool-like elasticity and bulkiness. The sheath-core composite fiber is a fiber that has two polymer characteristics or highlights the characteristics of one polymer. For example, nylon is used as the skin layer and polyester is used as the core layer to obtain fibers with good dyeability, soft hand feeling and rigidity; use The core layer with high refractive index and the skin layer with low refractive index can be made into optical fiber. If the island component is continuously dispersed in the sea component to form the sea-island composite fiber, and then the sea component is dissolved in a solvent, the continuous island component is left, and very fine ultra-fine fibers are produced. Split-type composite fibers appear in the form of thicker filaments during spinning, forming and post-processing. In the weaving process, especially in the finishing and sanding process, due to the compatibility of the two components and the adhesion of the interface. The knot is poor, each thicker filament splits into many filaments, and the composite form is different. The cross-sectional shape and thickness of the fiber after splitting are also different. The cross-section is triangular, and Figure (6) shows the split-type composite fiber, which becomes flat yarn after splitting. The split-type composite fiber production technology has been widely used in the manufacture of ultrafine fibers.

 

#8. Superfine fiber

 

Because the thickness of single fiber has a great influence on the performance of fabrics, chemical fibers can also be classified according to the thickness (linear density) of single fibers, and are generally divided into conventional fibers, fine fibers, superfine fibers and ultrafine fibers.

 

8.1 Conventional fiber

The linear density is 1.5~4dtex.

 

8.2 Fine denier fiber

The linear density is 0.55~1.4dtex, which is mainly used for light-thin or medium-thick fabrics like silk.

 

8.3 Superfine fiber

The linear density is 0.11~0.55dtex, and it can be produced by the two-component composite splitting method, the sea-island method, and the melt-blown method.

 

8.4 Very fine fiber

The linear density is below 0.11 dtex, which can be produced by the sea-island spinning method, and is mainly used in special fields such as artificial leather and medical filter materials.

 Very fine fiber

Compared with conventional synthetic fibers, ultra-fine fibers have the advantages of soft and waxy touch, soft luster, strong fabric coverage, and good wearing comfort. They also have the disadvantages of poor wrinkle resistance and high dye consumption during dyeing. Its main performance is detailed in the table below. Microfiber is mainly used to make high-density waterproof and breathable fabrics, artificial leather, imitated suede, imitated peach skin, imitated silk fabrics, high-performance wipes, etc.

  ultra-fine fibers

#9. New synthetic fiber

 

In the late 1980s, new synthetic fiber appeared in Japan. It became popular all over the world with its novel and unique supernatural style and texture, such as peach noodles and ultra-fine powder. The new synthetic fiber adopts brand-new modification and compounding technology from all steps of polymerization, spinning, weaving, dyeing and finishing, and sewing. It is a new type of fiber material that can not be compared with natural fibers and synthetic fibers in the past. According to its commodity form, the new synthetic fiber mainly includes super fluffy, super drape and super fine. According to its hand feeling, it can be divided into silk hand feeling, peach skin hand feeling, super fine powder hand feeling and new wool hand feeling.

 

9.1 Super fluffy

 

Among all synthetic fiber products for consumption, ultra-fluffy and high-texture fibers are the most, almost all of which are made of hetero-shrinkage mixed fibers or multi-phase mixing technology. In order to improve the bulkiness of fiber products, high heat shrinkable polymers and low shrinkage potential spontaneous elongation yarns have been developed one after another to make the fabric obtain better bulkiness.

 

9.2 Superfine

 

As a new synthetic fiber, the linear density of superfine fibers is very low, and the linear density of some varieties can reach 0.001dtex or more.

Next, it is mainly spun by the ultra-fine technology of composite spinning. The peach skin fabric thus developed has a super soft and delicate feel.

It is incomparable to natural fiber products.

 

9.3 Super drape type

 

The super-drape fiber is made by adding inorganic fine particles to the spinning solution, and then undergoing a weight reduction process to eliminate the inorganic fine particles after spinning and forming, so that countless micro-etchings are formed on the surface of the fiber. Due to the reduced friction between monofilaments, super-drape fiber products have super-drapability and a unique feel that is not as good as natural fibers.

 

#10. Easily dyeable synthetic fiber

Synthetic fibers, especially polyester fibers, have poor dyeability and are difficult to dye dark colors. Chemical modification can improve their dyeability and deepness. This modified synthetic fiber is called dyeability. Synthetic fibers mainly include cationic dyeable polyester fibers, cationic deep dyed polyamide fibers, and acid dyeable polyacrylonitrile fibers and polypropylene fibers. Easily dyeable synthetic fiber not only expands the dyeable range of the fiber and reduces the difficulty of dyeing, but also increases the variety of textiles.

 easily dyeable synthetic fiber

#11. High performance fiber

 

High-performance fibers have a special physical and chemical structure, one or more performance indicators are significantly higher than ordinary fibers, and the acquisition and application of these properties are often related to aerospace, aircraft, marine, medical, military, optical fiber communications, biological engineering, and robotics. It is related to high-tech fields such as large-scale integrated circuits, so high-performance fibers are also called high-tech fibers.

  high-performance fibers are also called high-tech fibers.

High-performance fibers are usually distinguished by their special properties, such as high strength and high modulus, high adsorption, high elasticity, and high temperature resistance

Flame-retardant, light-guiding, conductive, high-efficiency separation, anti-radiation, reverse osmosis, corrosion resistance, medical and pharmaceutical fibers and other fiber materials. High-performance fibers are mainly used in the manufacture of industrial textiles, but some of them can also be used to develop paving textiles and clothing textiles, and the performance of these two types of textiles can be significantly improved.

 

#12. Nanofiber

 

Fibers with a diameter of less than 100nm are usually called nanofibers (1nm is equal to 10 m, that is, 10 μm, which is only the length of 10 hydrogen atoms). At present, some people will add nano-scale (that is, the particle size is less than 100nm) powder filling The fiber of the material is called nanofiber.

 Nanofiber

At present, the thinnest nanofibers are chains of single carbon atoms. This carbon nanotube is known as the king of nanomaterials. The reason is that this material, which is so thin that it is difficult to observe by ordinary instruments, has magical capabilities: super high strength, super Flexible and strangely magnetic. Due to the short distance between carbon atoms and the small diameter of the carbon nanotubes, the fiber structure is not prone to defects. Its strength is 100 times that of steel and 200 times that of general fiber, and its density is only 1/6 of that of steel. The rope made with it can be pulled from the earth to the moon without being broken by its own weight. It has strange conductivity, both metal conductivity and semiconducting, and even different parts of a carbon nanotube can show different conductivity due to structural changes. Using it as a rectifier tube can replace silicon chips, which will cause major changes in electronics and make computers extremely small. Nano-devices made of carbon nanotubes can assemble nano-robots, such as mosquito planes, ant tanks, etc., which can be used in military and medical treatment. Carbon nanotubes can be used to make hydrogen storage materials and develop hydrogen into clean energy for human services. In addition, carbon nanotubes can also be used as invisible materials, catalyst carriers and electrode materials. Nanofibers can support the arrangement of "nanomachines" and connect integrated arrays of "nanomachines" into a large-scale system.

 

When the fineness of most materials reaches the nanometer level, their physical and chemical properties show unconventional properties, such as:

 

12.1 Surface effect

 

The smaller the particle size, the larger the surface area. Because surface particles lack the coordination of adjacent atoms, the surface energy is increased and extremely unstable. It is easy to combine with other atoms and exhibits stronger activity. After the fineness of the fiber reaches the nanometer level, the relationship between its diameter, specific length and specific surface area is shown in the following table.

 Surface effect

It can be seen from the above table that when the fiber diameter is 100nm, the specific surface area is more than 30 times that of the diameter of 10μm, while the specific surface area of the diameter of 1μm is only 10 times that of the diameter of 10μm.

 

12.2 Small size effect

When the size of the particle is as small as the wavelength of the light wave, the De Broglie wavelength for conducting electrons, and the coherence length or transmission depth of the superconducting state, the periodic boundary conditions will be destroyed. The properties of light, electromagnetism, and thermodynamics will change, such as lower melting point, color separation, absorption of ultraviolet rays, and shielding of electromagnetic waves.

 

12.3 Quantum size effect

When the particle size is small to a certain value, the electron energy level near the Fermi level changes from quasi-continuous to discrete energy level. At this time, the substance that was originally a conductor may become an insulator, and the original insulator may become a superconductor. .

 

12.4 Macroscopic quantum tunneling effect

The tunnel effect means that tiny particles can pass through an object under certain circumstances, just like there is a tunnel inside.

 

The manufacture of nanofibers can be roughly divided into three categories: molecular technology preparation methods, spinning preparation methods, and biological preparation methods.



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