Properties and functions of special yarns

Special yarn refers to yarn with special appearance and structure, irregular cross-section distribution or special and changeable. Mainly divided into textured yarn, fancy yarn, core-spun yarn and so on. Compared with ordinary yarns, they have some changes in appearance and structure, so their yarn properties and wearing characteristics have also changed, which is unique.

1. Properties and functions of textured yarn

Textured yarn is evolved from ordinary yarn, that is, ordinary synthetic filaments are deformed to change their appearance, and chemical precursors are deformed by heating, machinery or air jet, so that straight filaments become yarns with curly, spiral, coil and other appearance characteristics, thus showing bulkiness and flexibility.

There are many processing methods of textured yarn, so the shape of textured yarn is different. Knife edge crimping method is to bend and brush the heated monofilament or multifilament near the knife edge when it is cooled. One side of the fiber near the knife edge is compressed and the other side is stretched to form crimping. False twist textured fiber is made by twisting → heat setting → untwisting → heat setting and other processes. The stuffing box method is to send the fiber into the heating tube, and at the same time, it is highly compressed and heat-set, which is curly; Air jet texturing method is to use high-pressure air flow to impact the precursor through the nozzle, blow the filament loose, make it displace in turbulence, entangle with each other, and stretch the yarn without tension. At this time, the fiber will produce irregular rings and curved ripples. The air jet can be compressed air or steam. Gear crimping textured fiber is to pass the long tow through a pair of heated gears, on the one hand, to give the filament a gear, on the other hand, to heat set, so as to obtain wavy textured yarn.

The yarn made of ordinary chemical fiber lacks fluffiness and coverage, so it is difficult to meet the requirements of softness and elasticity of clothing. Although textured yarn is not different from ordinary yarn in structure, it greatly improves the hygroscopicity, breathability, softness, elasticity and warmth retention of yarn and clothing materials, so that textured yarn fabric not only maintains the wrinkle resistance and shape retention of synthetic fiber itself, but also has the excellent comfort of natural fiber fabric, which undoubtedly expands the application range compared with ordinary yarn.

The excellent wearability of textured yarn comes from the following reasons: (1) the curled shape is beneficial to the formation of air layer in yarn, which increases the warmth retention of yarn; Because of the deformation treatment and the separation of monofilaments, the breeze can penetrate the clothes made of deformed yarn fabric, thus strengthening the heat exchange and evaporation of water and contributing to the comfort of wearing; At the same time, the hairiness and bulkiness of the surface can make the fabric not close to the skin, thus enhancing the softness of the hand. The textured yarn can be used to weave fabrics similar to natural fibers, such as wool, silk, hemp and other products. Commonly used textured yarns are as follows:

? ① Elastic yarn: it can be divided into high elastic yarn and low elastic yarn.

A. High elastic yarn: excellent elastic deformation recovery ability, and average canopy performance. Mainly used for elastic fabrics (tights, socks, etc.). ), mainly nylon filament textured yarn. High elastic yarn is a kind of high tensile yarn, and its elongation is above 50%.

B. Low elastic yarn (deformed elastic yarn, improved elastic type): with appropriate elasticity and bulkiness, it is used for knitting and weaving fabrics, underwear, sweaters, etc. It has low elastic requirements and a certain volume. Good handle and dimensional stability, low elastic yarn is mainly made of polyester filament, and a few are made of synthetic fibers such as polypropylene fiber and nylon. Low elastic yarn is a kind of low tension yarn, and its extensibility is about 20%-30%.

? (2) bulky staple yarn (fluffy textured yarn): a yarn with high bulkiness made of acrylic fiber due to its special thermal shrinkage. This textured yarn is mainly fluffy and elastic, and its elongation is generally below 15%. Mainly used in wool, wool-like woolen cloth, wool-like knitted fabrics, sweaters, hats, scarves and so on.

In addition, there are some textured yarns (such as air textured yarns) made by other texturing methods, which are mostly used to imitate some characteristics of natural fibers to make up for the shortcomings of ordinary synthetic fabrics in appearance, texture and durability.

2. Characteristics and functions of fancy yarns

Fancy yarn refers to the yarn with special appearance, feel, color change, structure and texture obtained by various processing methods. Because of the different processing methods, fancy yarns are different from ordinary yarns in structure. Their main characteristics are uneven thickness of cross section and different colors, and some varieties have special appearances such as small rings or knots.

Fancy yarn is not as good as ordinary yarn in strength and wear resistance, and easy to pilling and spinning, but it is better than ordinary yarn in appearance performance. By making various patterns and matching various colors, we can get novel and unique appearance effects. Fancy yarn can be used to process clothing materials, such as women's yarn and tweed woven into various colors; Can also process decorative materials, such as various hand-woven wool, curtain furniture and other decorative fabrics. The fabric has outstanding patterns, strong three-dimensional sense and unique style. Fancy yarns can be divided into the following categories according to their structural characteristics and formation methods:

A. Colored yarn (thread): rainbow thread, printed thread, mixed dotted line and colored dotted line.

? (1) Mixed-color yarn (thread): yarn with two-color or multi-color mixing effect.

(1) Mix fibers and yarns of different colors; Printing and mixing the yarn strips; Fibers with different dyeing properties are mixed and dyed to produce different colors. If the yarns are mixed evenly, the fabric color changes smoothly and evenly; If the yarn color is uneven and the shades are different, the fabric color changes obviously, and even there is a sense of jumping, such as "catching flowers" and "raining" effects, which can be obtained in this way, adding subtle changes to the clothing.

② Single yarn strands with different colors: For example, the flower strand (AB thread) consists of two kinds of spun yarns with different colors. If the two colors A and B are complementary, they will have a flashing effect after combination.

(2) Interval dyeing line (segmented dyed yarn): the yarn is dyed in segments by special devices in the process of advancing, so the appearance of this colored yarn is segmented alternately with dyed and undyed yarns, or arranged and continued in different colors, like a rainbow; Or printed yarns with different color segments made by interval dyeing method.

(3) Ligation: the twisted yarn is dyed after ligation, and the knotted part is dyed, and the knotted part is not dyed, but white spots are left. The color change of the bandage is a natural and unique transition from white to a certain color. The width, tightness and interval of ligature are different, and the color effect is different. The final "color" of the fabric is even more unpredictable.

(4) Color point yarn (money): short and small monochromatic or multicolor point fiber particles are unevenly distributed on the surface of yarn or monochromatic or multicolor points on yarn, with short length and small volume. Color-point yarn color-point fiber particles are eye-catching and full of embellishment, and the woven fabric is colorful, with different colors in every place. It can be used as a fabric for women's and men's casual wear. For example, the traditional woolen steel flower is woven with colored dots.

B fancy thread: the basic structure of fancy thread consists of three parts: core thread, decorative thread and fixed thread. It can be divided into overfeeding type (loop thread, bead thread, loop thread and spiral thread) and control type (knot thread, big belly thread, slub thread and napping). )。

? Core yarn: located in the center of yarn, it is the main part of yarn strength.

Decorative yarn: it forms the fancy effect of fancy yarn and plays a decorative role.

Fixed yarn: used to fix the pattern formed by decorative yarn, usually using strong spun yarn.

(1) Slub yarn: It has the appearance of uneven thickness distribution, that is, one section is thick and the other is thin, and the change can be regular or random. The surface of the fabric presents undulating texture, which is prominent, unique in style and strong in three-dimensional sense. It can be used to knit fabrics and sweaters in different seasons, reflecting the change of thickness. Such as: light summer fabrics, heavy winter fabrics and various linen-like fabrics. All kinds of linen-like fabrics are made of slub yarns with different specifications and different spacing, which makes the surface of the fabric show rough, natural and concave-convex slub patterns, and makes people feel a kind of true feelings. ?

(2) terry yarn (also called loop yarn): decorative thread is wound around the core to form a loop, and the size, distance and color of the loop can be changed. According to the overfeeding and twisting size of the decorative thread relative to the core thread, various wavy lines, small loop lines, large loop lines, braided lines and beaded lines can be formed. Terry yarn feels soft and plump, and its fabric surface has a layer of terry or bead effect, which is fluffy and warm. But wreaths are easy to brush and pull, so be more careful when wearing and washing. When the decorative thread is strongly twisted, it will naturally be braided to form a braided thread. Mainly used for yarn-dyed woven women's tweed, worsted tweed, woolen tweed, coat tweed and hand-woven woolen cloth.

(3) Knot (also called knot): It is usually composed of two groups of yarns, the core thread and the decorative thread, and the knot is formed by the decorative thread. The decorative yarn forms knots around the core yarn for a short distance. The knots are long or short, and the spacing and color can be changed. Long knots are also called caterpillars, and short knots can be monochrome or multicolor. Strong and prominent knots on yarn can best show uneven or uneven particle effect. Fine weavers weave fabrics and coarse weavers knit sweaters, which has a sense of jumping. ?

(4) Big belly yarn (also called broken silk thread): In the process of yarn twisting, a small bundle of fibers is added at intervals, and this bundle of fibers is wrapped in the twisted yarn to form local protrusions. By changing the size and color of the added fiber bundles, we can form belly yarns with different protruding effects and dull color effects. Abdominal yarn fabric has a strong three-dimensional sense, and the raised pattern composed of coarse knots is like a cloud in the sky, with fine sections weaving the sky and thick sections embroidered with clouds.

(5) Spiral: Decorative yarn is spirally wound on yarns with high yarn count, large twist or different raw materials, colors, luster, etc. And then twisted to form a spiral effect. Decorative yarn is generally small and thick, and it is wound on the yarn with small twist. After twisting, the relaxation of the yarn can strengthen the spiral effect and make the yarn look like a rooster. Helical lines mostly appear in the form of two-color, three-color or color change, with good elasticity, fluffy fabric and corrugated patterns.

(6) Wool drawing: Drawing decorative yarns to make them look long and short. The product has a strong fuzz feeling, feels plump and soft, and its fabrics and clothing are extremely rich in fuzz and fullness. Pulling wool is mostly used for woolen tweed, hand-woven wool, sweaters and scarves.

C. Special fancy threads: honeysuckle thread, chenille thread, caterpillar thread, ribbon thread, etc.

(1) Chenille yarn: Chenille yarn, also known as Chenille yarn, is spun with two strands as the core yarn and feather yarn sandwiched between them by twisting. The fiber is held on the plied core yarn, and the surface of the yarn is covered with towering fiber fluff, which looks like a flat or round bottle brush. Soft and plump fluff makes the fabric feel very velvet, drape, smooth and elegant, without complicated organizational structure, and has special effects. Used for knitting wool fabrics, casual clothes and indoor decorative fabrics, hand-made sweaters.

(2) honeysuckle thread: gold, silver or other aluminum pieces are sandwiched between two layers of transparent polyester films, and then processed into gold and silver threads. After using the gold and silver thread, the flashing luster is gorgeous and dazzling, and the products appear luxurious, elegant and dazzling.