As the most widely used chemical fiber, polyester fiber has good fiber-forming properties and mechanical properties, high strength, good light resistance, heat resistance, acid and alkali resistance, good processability and easy spinning, and can be pure Spun, blended or interwoven. Polyester fabrics are washable and wear-resistant, easy to iron and wrinkle-resistant, and are widely used in clothing, home textiles, decoration and industrial fields. However, polyester fiber also has shortcomings such as poor hygroscopicity, non-sweat-absorbent fabrics, stuffy feeling when worn, poor anti-static ability, and easy contamination with dust, which greatly restricts the application and development of polyester fiber.
In order to improve the wearing comfort of polyester fiber, it is necessary to make the fabric have good hygroscopicity and quick-drying properties, making the clothing light and comfortable. After deforming the fiber cross-section It can significantly improve the hygroscopicity of the fiber, so people have been committed to research and development of special-shaped cross-section polyester with functions such as moisture absorption and perspiration.
Special-shaped fibers are chemical fibers with special cross-sectional shapes spun through spinnerets with a certain geometric shape (non-circular). Also called “special-shaped cross-section fiber”. The so-called special-shaped fibers are made from identical synthetic fibers into fibers with deformed cross-sections. Like natural fibers, they can be made into triangular, star-shaped, multi-lobed shapes, etc. They can be special-shaped cross-section fibers, special-shaped hollow fibers, or composite special-shaped fibers. Special-shaped fibers are relative to round fibers. It is extruded from a spinneret hole with a special geometric shape, so that the cross-section is a fiber with a certain geometric shape. The special-shaped fibers currently produced mainly include three-shaped, fan-shaped, hollow-shaped, etc.
Special-shaped fiber was originally introduced by the American DuPont Company in the early 1950s with a triangular cross-section, and then Germany developed a pentagonal cross-section. In the early 1960s, the United States developed hollow fibers with good warmth retention properties. Japan began to develop special-shaped fibers in the 1960s. Subsequently, countries such as the United Kingdom, Italy, and the former Soviet Union also successively developed such products. Since the manufacturing and textile processing technology of special-shaped fibers is relatively simple, with low investment and quick results, it has developed relatively quickly. The development of special-shaped fibers in my country was in the mid-1970s. Processing techniques have been improved in spinneret manufacturing, improving the spinnability of the plates. In terms of spinning, there is a mature and complete process. In terms of textile products, they mainly imitate various natural fibers.
Characteristics of special-shaped fibers
Compared with circular fiber cross-section fibers, special-shaped fibers have the following characteristics: characteristic.
1. Surface gloss
Fiber gloss has a great relationship with fiber cross-sectional shape. When a beam of parallel light irradiates the fiber surface with different cross-sectional shapes, different gloss effects will occur.
For example, in a triangular cross-section, when light shines on it, it can be transmitted through the edges inside the fiber. In this way, the gloss will be weak at the edges where total reflection occurs, while the gloss outside other edges will be weak. Just strong. When the incident angle changes, the edges that produce total reflection will also change, resulting in a “flash” effect. In addition, due to the prism effect of the triangle, the dispersion effect is produced when the light is emitted, giving people a special feeling. Therefore, the special-shaped fiber changes the “aurora” of the round fiber. Especially for hollow special-shaped fibers, the reflective layer is correspondingly thinned and internal reflection occurs at the same time. The combination of surface reflection and internal reflection can enhance the intensity of reflected light, so hollow triangular fibers have better gloss effects.
For another example, in the contrast gloss experiment of ordinary acrylic fiber, special-shaped acrylic fiber and silk fabric, silk has the highest contrast gloss, and special-shaped acrylic fiber has a higher contrast gloss than round fiber, which is close to silk gloss.
2. Anti-wrinkle and anti-snapping properties
The elastic modulus of special-shaped fibers is higher than that of circular cross-sections, so they have stronger resistance to deformation and better anti-wrinkle effects. Just like an I-beam of the same length and weight has better bending resistance than a round steel.
3. Antistatic and hygroscopicity
After the fiber is deformed, its surface area and voids increase , the moisture regain of the fabric increases, and the more complex the cross-section, the higher the moisture regain. For example, the moisture regain of hexagonal nylon filament can reach 5.2%, while the moisture regain of circular cross-section fabric is only 4.8%. Due to the increased hygroscopicity of the shaped fibers, the antistatic effect is improved.
4. Pilling resistance
Because some synthetic fiber raw materials are prone to pilling, their During the use of the fabric, some fibers form entangled balls and adhere to the surface of the fabric, reducing the use value of the fabric. Due to the strong cohesion of the special-shaped fibers, the small hairs are not easy to slip out, so the pilling phenomenon is greatly reduced. The anti-pilling performance is related to the deformation degree of the cross section. The greater the deformation degree, the better the pilling resistance. For the same flat synthetic fiber, under the same linear density, the greater the flatness, the better the anti-pilling performance.
5. Dyeing performance
Due to the increased surface area of special-shaped fibers , the dyeing rate can be improved. However, it also increases the reflection of light, so from a visual effect, with the same dye adsorption amount, the resulting color appears slightly lighter. Therefore, in order to obtain the same depth of dyeing in appearance, 10% to 20% more dye must be used when dyeing special-shaped fibers than circular cross-section fibers. However,�The brightness of special-shaped fibers is higher.
6. Anti-fouling properties
Due to the special-shaped fiber’s resistance to light The reflection effect is strong and the light transmittance is low, making the dirt particles appear smaller, so it has a perceived anti-fouling performance. In addition, the surface area is relatively large. After being made into fabric, it is reflected in people’s vision. The covering performance of the fabric is relatively good and it is not easy to be stained. The following is the covering performance and stain resistance of four polyester fiber samples with circular and triangular cross-sections.
Classification of special-shaped fibers
The varieties of special-shaped fibers are quite rich, and they can generally be classified according to their cross-sectional shapes. It is divided into several types such as triangular, polygonal (five-star, five-leaf, hexagonal, branch type), flat ribbon, hollow fiber and other types. There are also special-shaped fibers such as eight-leaf shape, lotus root shape, mosquito coil-like spiral shape, etc. These fibers have their own characteristics, and their cross-sectional shape depends on the shape of the spinneret holes on the spinneret during spinning.
Some special-shaped fibers
C-shaped hollow: warm, Moisture-absorbing and quick-drying effect, developed for use in home textile plush products.
Cross: It has better moisture absorption and perspiration effect. It is popularized by warp knitting double needle bed and has been widely used in circular knitting machines. Produces double-sided pique fabric (moisture-wicking).
Double cross: moisture absorption, quick drying, crisp feel, developed for home textile plush products.
Dumbbell: It has the effects of warmth retention, moisture absorption and quick drying, and is developed for use in home textile plush products.
Flat: It has a warm effect, strong gloss and soft hand feel. It has been widely used in warp knitting double needle beds.
Triangle: bright luster and crisp feel.
Plum blossom shape: moisture absorption and quick drying, unique style and feel, developed for home textile plush products.
Hollow: excellent warmth retention and fluffiness, developed for use in home textile plush products.
H-shaped (H): Moisture-absorbing, quick-drying, crisp feel, developed for use in home textile plush products.
Application of special-shaped fibers
Blended wool-like fabrics
Using special-shaped cross-section polyester fibers for blending, weaving wool-like fabrics can produce better results Faux fur effect. It has the characteristics of high bulkiness, good warmth retention, thick fabric and light weight.
Silk-like fabric
Silk-like fabric is woven with special-shaped cross-section polyester. The resulting fabric has a unique luster, is light and smooth, has a soft hand feel, is stiff and does not need to be ironed. Easy to wash and quick to dry. Especially after the fabric is further imitated, the fabric will have a silk style. Polyester cross-sections are available in three-lobed, five-lobed and triangular shapes. Choose trilobal or five-lobed fabrics with a softer luster. </p
