When chemical fibers are wool-like from a fiber angle, […]
When chemical fibers are wool-like from a fiber angle, they are initially based on the characteristics of the length and fineness of wool fibers. During the spinning process, chemical fibers are spun to a length and linear density similar to wool fibers,polyester yarn such as a linear density of 2.5-3.3 dtex and a length of 51-102 mm. Currently used wool-like chemical fibers include high-shrinkage fibers, profiled fibers, composite fibers, cationic dyeable polyester, flame retardant fibers, ultra-fine fibers, air-textured yarns, and blended yarns.
1. High shrinkage fiber
High shrinkage fiber refers to a fiber that can produce greater shrinkage under the action of heat. Common high-shrink fibers include high-shrink acrylic and high-shrink polyester.
High shrinkage acrylic fiber: Since acrylic fiber does not have a crystalline area and an amorphous area in the strict sense, its ordered structure makes it unable to prevent the large thermal movement of the segment, so that the acrylic fiber has a unique thermal elasticity and can produce shrinkage , Can produce acrylic fiber bulk yarn.
Production method: There are two methods for producing high-shrink acrylic fiber, namely the stretching method and the chemical modification method. The drawing method is to stretch the acrylic macromolecule chain multiple times when it is higher than the glass transition temperature of the acrylic fiber, and then orient it along the fiber axis, and then cool it sharply to temporarily fix the shape and tension of the fiber macromolecular chain When the acrylic is treated in a relaxed state, it causes significant shrinkage of the fiber in the length direction. The chemical modification method is to increase the content of the second monomer methyl acrylate, or use a thermoplastic second monomer to copolymerize with acrylonitrile to reduce the arrangement tightness of the fiber molecules, which can significantly improve the shrinkage of acrylic fiber.
Production method of high-shrink polyester: High-shrink polyester is generally obtained by modifying crystalline polyester. There are two main production methods: one is the use of special spinning and drawing processes, such as POY yarn after low-temperature stretching, low temperature The process such as setting can produce high shrinkage polyester with a shrinkage of 15% -50% in boiling water; the other is to use a chemical modification method to produce a modified copolyester and then spin it.
2. Shaped fiber: Shaped fiber refers to a fiber with a non-circular cross-sectional shape.
Production of special-shaped fibers: special-shaped fibers are spun with non-circular cross-section spinneret holes. They are generally spun by melt spinning or solution spinning. They are mainly triangular, polygonal and multi-lobed. , Flat, hollow and multi-hollow. The purpose is to improve the properties of synthetic fiber such as hand, gloss, hygroscopicity and bulkiness.
3. Composite fiber
Composite fiber is composed of two or more polymers, or the same polymer with different properties, compounded in a certain way. Composite fibers can be made into wool-like fibers with special functions such as high crimp, easy dyeing, flame retardant, antistatic, and high moisture absorption. According to the distribution and arrangement of each component in the fiber, composite fiber can be divided into side-by-side type, sheath-core type and matrix-fibril type. By selecting components with different shrinkage ratios, the side-by-side composite fibers can be made into crimped fibers, so they are often used in chemical fiber wool.
Synthetic fiber wool-like product development: The natural curling property of wool is due to the bilateral structure of normal cortex and metacortical cells. To imitate the curling characteristics of wool fibers.
When spinning chemical fibers, two components with different shrinkage ratios can be used to produce side-by-side composite fibers with different shrinkage ratio components on the same fiber cross section, such as polyamide and polyester, polyurethane Polyether and polyacrylonitrile are self-crimping side-by-side bicomponent conjugate fibers. The fibers have good crimping durability, bulkiness, resilience, and heat retention. it is good.
4. Flame retardant fiber: In order to imitate the non-flammable characteristics of wool fiber, wool-like chemical fiber can be made into flame retardant fiber.
Production of flame-retardant fibers: Flame-retardant fibers are generally produced by copolymerization or blending methods. The copolymerization method is to use a monomer containing flame retardant elements (such as Cl. Br, P, etc.) to prepare a flame-retardant fiber-forming polymer by copolymerization, and then spin to obtain flame-retardant fibers. The blending method is to add the flame retardant to the spinning melt or solution, mix and spin to obtain the flame retardant fiber.
At present, the commonly used wool-like flame retardant fibers are: flame retardant polyester, flame retardant eye nylon, flame retardant acrylic and so on.
5. Ultra-fine fibers: Japan refers to fibers with a linear density of less than 0.3 dtex as ultra-fine fibers. Microfiber has the advantages of soft feel and comfortable wearing
Production of ultra-fine fibers: There are two main types of ultra-fine fibers: direct spinning and composite spinning. The direct spinning method uses the traditional melt spinning method to produce ultrafine fibers. The composite spinning method is to use composite spinning technology to spin composite fibers, and then use mechanical treatment or chemical treatment to separate the components in the composite fibers from each other, or use a solvent to