Question 1: What are synthetic fibers? Synthetic fibers
One of the two major categories of chemical fibers. A general term for chemical fibers made from synthetic polymer compounds. Polyamide cellulose, polyester fiber, polyacrylonitrile fiber, and polyvinyl formal fiber are the four major varieties of synthetic fibers in my country. In addition, polypropylene fiber and polyvinyl chloride fiber also have a certain output.
The main varieties of synthetic fibers are as follows: (1) According to the main chain structure, carbon chain synthetic fibers can be divided, such as polypropylene fiber (polypropylene), polyacrylonitrile fiber (acrylic fiber), polyvinyl formal fiber (Vinylon); heterogeneous chain synthetic fibers, such as polyamide fiber (nylon), polyethylene terephthalate (polyester), etc. (2) According to performance and function, it can be divided into high-temperature-resistant fibers, such as polybendazole fiber; high-temperature corrosion-resistant fibers, such as polytetrafluoroethylene; high-strength fibers, such as poly(p-phenylene terephthalamide); radiation-resistant fibers, such as Polyimide fiber; flame retardant fiber, polymer optical fiber, etc. There are three major processes in the production of synthetic fibers: synthetic polymer preparation, spinning and post-processing.
New and functional synthetic fibers:
1 Microfiber
Polyester with fiber fineness of 0.5→0.35→0.25→0.27 (dpf), specifications Available: 50/144, 50/216, 50/288 ultra-fine polyester. There is also ultra-fine nylon Tactel fiber produced by DuPont, with a diameter of less than 10 μm. The garments made have an excellent soft feel, are breathable, waterproof and windproof.
2 Composite fiber (island type and split type)
Mainly composed of PET/COPET or PET/PA, island type fiber: fineness can reach 0.04-0.06dpf, and Easy-to-shrink island-shaped composite fiber, which can be used as suede-like outerwear, home textiles and industrial fabrics. The composite segmented fiber has a fineness of 0.15-0.23 (dpf), including DTY silk 80/36×12, and can also be used to make imitation suede and peach skin textiles.
3 Moisture-absorbing and sweat-wicking fibers
To achieve the moisture-wicking function of textiles, methods can be adopted: (1) Fiber cross-section specialization: Y-shaped, cross-shaped, W-shaped and bone Shape, etc., increase the surface area, and there are more grooves on the surface of the fiber, which can improve the effect of transmitting water vapor. (2) Hollow or porous fibers: Use capillary action and the principle of increasing surface area to quickly diffuse sweat out. (3) Chemical attack on the fiber surface: increase the hydrophilic groups on the fiber surface (grafting or cross-linking method) to achieve rapid moisture absorption. (4) Hydrophilic agent finishing: directly use hydrophilic additives to impart hydrophilicity to fabrics or fiber yarns during the post-printing and dyeing process. (5) Adopt a multi-layer fabric structure: use hydrophilic fibers as the inner fabric to quickly absorb the sweat produced by the human body, and then conduct it to the outside through the gaps in the outer fabric to achieve comfortable and cool performance.
Moisture-wicking fibers include Shin Kong Synthetic Fiber CoolTech, Chung Hsing Textile Co., Ltd.’s product Coolplus, Nanya Plastics Industry Co., Ltd.’s Delight fiber, Far East Textile Co., Ltd.’s moisture-wicking polyester Topcool fiber, Technofine fiber (PET with W-shaped structure) produced by Asahi Kasei Co., Ltd. of Japan, CoolMax fiber of DuPont, etc.
4 Easily dyeable polyester fiber
(1) Introducing a dyeable group (third monomer) into the molecular structure, such as: introducing an anionic dyeable group into the molecule Cationic dye-dyeable polyester CDP or HCDP and acid dye-dyeable polyester with cationic groups introduced into the molecule;
(2) Polypropylene terephthalate (PTT) that changes the regularity of the molecules ) fiber and polybutylene terephthalate (PBT) fiber.
PTT fiber already had this polyester production patent in 1941. Due to the high cost of raw materials for producing 1,3 propylene glycol (PDO), industrial production has not been achieved. It was not until 1995 that the German Degussa Company industrialized the production of 1,3 propylene glycol, which greatly reduced the cost. Subsequently, the American Shell Company launched the Corterra Polymer product in May 1995, and built an annual output of 2.2kt propylene glycol and an annual output of 5.5ktp door production lines. There are filament and short fiber varieties called Corterra.
There are also PTT fibers called Sorona produced by DuPont Company of the United States, Solo of Japan's Asahi Kasei Company, South Korea's SK Chemical Company, Taiwan's Hualong and China... >>
Question 2: The characteristics of synthetic fibers are: What are the main performance characteristics of synthetic fibers
1. Polyester: the largest variety with the highest output among synthetic fibers.
There are multiple trade names: the trade name for polyester in the UK is "Terylene"; the trade name for polyester in the United States is "Dacron"; "polyester" is our country's trade name.
Structure and performance: The structural shape is determined by the spinneret. The cross-section of conventional polyester is round and has no central cavity. The fiber macromolecules have high crystallinity and high orientation, so the fiber has high strength (20 times that of viscose fiber), good elasticity and not easy to wrinkle, stiffness and good shape retention, good light and heat resistance, quick drying and no need to iron after washing. Wearability is good. Polyester is relatively stable against general chemical reagents and resistant to acids, but does not require high-humidity treatment with concentrated alkali. This property is used to process polyester. The surface of the fiber is corroded, the weight is reduced, and the fineness becomes thinner, which can produce a silk style (i.e. simulation). This method is called alkali reduction treatment. Polyester fiber has poor hygroscopicity, poor air permeability and sweat absorption. It feels stuffy when worn. At the same time, its dyeability is also poor, so special dyes are needed. Or equipment and process conditions, dyeing under high humidity and high pressure. In order to improve its dyeability, cationic dyeable polyester is currently on the market. If you want to improve the wearability of polyester, you can use polyester with other natural fibers (such as cotton) or regenerated cellulose. Fibers (such as viscose) and other blends.
2. Nylon: (my country’s trade name) is the earliest synthetic fiber, with varieties including nylon 6 and nylon 66; like polyester, there are other trade names, and the American trade name is (Nylon) Nylon, Japan's trade name is (Nailon) nylon. Our country mainly uses nylon 6, and its dyeing performance is better than nylon 66.
Nylon fiber is straight and smooth longitudinally, and its cross-section can be round or other shapes. The most outstanding feature of nylon is its excellent wear resistance (10 times higher than cotton fiber), good strength and elasticity. Therefore, it has excellent durability and is often used to make socks and ropes. Its specific gravity is smaller than polyester and other fibers, so it is light to wear. Nylon fiber has poor hygroscopicity and good waterproof and windproof properties. It is suitable for mountaineering clothing, parachutes, and wind and raincoats. Due to the low moisture regain and poor hygroscopicity, the fabric is prone to static electricity and feels stuffy. However, after modification and blending with other fibers, its wearing properties have been greatly improved.
3. Acrylic fiber: Acrylic fiber is mainly made of short fibers. Because it resembles wool, it is called "artificial wool". Acrylic fiber has unique thermal extensibility and is suitable for making bulked yarn, wool, knitted fabrics, artificial fur and other products. Acrylic fiber feels soft and plump, easy to dye, and has bright colors. The elasticity is not as good as wool, polyester and other fibers, especially after repeated stretching, the residual deformation is large. Therefore, the cuffs and collars of clothes made of acrylic fiber are easy to deform. Acrylic fiber is less hygroscopic than nylon fiber and is prone to static electricity and pilling. Acrylic fiber has low thermal conductivity and light texture, so it has good warmth retention. It also has excellent sunlight resistance and is resistant to insects and mold. It is widely used in knitted clothing.
4. Polypropylene: rich sources of raw materials, low price, simple production process and rapid development. The biggest feature of polypropylene is its small specific gravity, which is lighter than water (3/5 of cotton fiber) and is the lightest fiber. The product has medium elasticity and resilience, and is not easy to wrinkle or pill. It is difficult to dye polypropylene, which is usually liquid dyeing. The hygroscopicity of polypropylene fiber is extremely poor, but polypropylene has a strong wicking effect. Water vapor can be eliminated through the capillaries in the fiber. After being made into clothing, its comfort is better, especially Polypropylene's microfiber can transfer sweat faster due to its increased surface area, keeping the skin comfortable. Polypropylene fiber has particularly poor light resistance and light resistance, is prone to aging, and has poor heat resistance. It begins to shrink above 100°C.
5. Spandex: It is a kind of highly elastic fiber. The international trade name is Spandex. This fiber was born in 1959 by DuPont Company in the United States and named Lycra.
Spandex has higher elasticity than other fibers, large deformation capacity, good elastic recovery performance, and a recovery rate of 90% when elongated to 500%. It can be dyed into various colors, has a smooth feel, low moisture absorption, lower strength than ordinary fibers, and is light and It is soft and has good acid, alkali and light resistance. Generally, bare silk is rarely used directly. Spandex is often used as the core, and it is imitated with cotton, wool, silk, polyester, nylon, etc. to form core-spun yarn, wrapped yarn, etc. It is an elastic fabric that makes the fabric soft, comfortable, close-fitting, and stretches freely. It is widely used. As long as the fabric contains a small amount of spandex (3%~5%), the elastic recovery ability of the fabric can be significantly improved.
6. Vinylon: less used in clothing and more used in industry. The appearance and feel of the fabric are like cotton, and its elasticity is not as good as polyester and other synthetic fibers. The fabric wrinkles easily and has poor dyeing performance. But its moisture content is worse than other synthetic fibers,...>>
Question 3: What are the spinning methods of synthetic fibers? Spinning methods of synthetic fibers
Overview of the spinning of synthetic fibers
The spinning of synthetic fibers is a process in which polymers are made into textile fibers with the basic fiber structure and its comprehensive properties
The spinning method of synthetic fibers
Mainly divided into 3 types
Melt spinning
The polymer is heated and melted into a melt, which is then pressurized and condensed into filaments by spraying a thin stream through a spinneret. .
Dry spinning
The polymer is prepared into a solution, which is pressurized to spray a thin stream through a spinneret, evaporating the solvent into filaments.
Wet spinning
The polymer is prepared into a solution, which is pressurized and sprayed through a spinneret to form a fine stream that diffuses bidirectionally through the coagulation pool and solidifies into filaments. Both dry and wet methods are called solution spinning because they both use solvents to dissolve polymers.
Question 4: During the spinning process, what structure of the fiber will change? Spinning method of synthetic fiber. Overview of spinning of synthetic fiber. Spinning of synthetic fiber is to make a polymer into a fiber with a basic structure. The process of spinning fibers and their comprehensive properties. The spinning methods of synthetic fibers are mainly divided into three types
Melt spinning
The polymer is heated and melted into a melt, which is pressurized and passed through a spray gun. The filament head sprays a thin stream and condenses it into filament.
Dry spinning configures the polymer into a solution, sprays a thin stream through the spinneret under pressure, and evaporates the solvent into filaments.
In wet spinning, the polymer is configured into a solution, which is pressurized and sprayed through a spinneret to cause a fine flow to diffuse bidirectionally through the coagulation pool and coagulate into filaments. Both dry and wet methods are called solution spinning because they both use solvents to dissolve polymers.