Commonly used wool-like chemical fiber production method

When chemical fibers are wool-like from the fiber angle, they are initially based on the length and fineness characteristics of the wool fibers. In the spinning process, the chemical fibers are spun into a length and linear density similar to those of the wool fibers, such as a linear density of 2.5 to 3 dtex and a length of 51 to 102 mm. At present, commonly used wool-like chemical fibers include high-shrinkage fibers, shaped fibers, composite fibers, cationic dye-dyeable polyester, flame-retardant fibers, ultrafine fibers, air-deformed filaments, and mixed-fibers.

1 high shrinkage fiber

High shrinkage fibers are fibers that are capable of producing large shrinkage under the action of heat. Common high shrinkage fibers are high shrinkage acrylic and high shrinkage polyester.

1.1 High shrinkage acrylic fiber Because acrylic fiber does not have a crystallization zone and an amorphous zone in a strict sense, its order structure makes it unable to prevent the large thermal movement of the chain segment, thus making the acrylic fiber unique in thermoelasticity and capable of shrinking. , can produce acrylic expanded yarn.

1.1.1 Production method

There are two methods for producing high shrinkage acrylic fibers, namely stretching and chemical modification. The stretching method is performed at a temperature higher than the glass transition temperature of the acrylic fiber, and the fiber macromolecular chain is stretched and oriented along the axial direction of the fiber, and then rapidly cooled to temporarily fix the shape and tension of the fiber macromolecular chain. When the acrylic fiber is treated in a relaxed state, it causes a 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 to copolymerize the thermoplastic second monomer with acrylonitrile to reduce the tightness of the fiber molecules, and to significantly increase the shrinkage of the acrylic fiber.

1.2 high shrinkage polyester

1.2.1 Production methods High shrinkage polyester is generally obtained by modifying crystalline polyester. There are two main production routes: one is to use special spinning and drawing processes, such as POY wire after low temperature stretching and low temperature setting. The process can produce a high shrinkage polyester with a boiling water shrinkage of 15% to 50%; the other is a chemical modification method to produce a modified copolyester and then spinning.

2 shaped fiber

The shaped fiber refers to a fiber whose cross-sectional shape is non-circular.

2.1 Production of shaped fibers

Shaped fibers are spun from non-circular cross-section shaped spun yarns. They are usually spun-spun or can be produced by solution spinning. They are mainly triangular, polygonal and multi-lobed, flat and hollow. Shape and multiple hollow shapes. The purpose is to improve the hand, gloss, moisture absorption, bulkiness and other properties of synthetic fibers.

3 composite fiber

A composite fiber is a composite of two or more polymers or polymers of the same performance in a certain manner. The composite fiber can be made into a fiber similar to wool with high curl, easy dyeing, flame retardant, antistatic, high moisture absorption and the like. The composite fiber can be mainly classified into a side-by-side type, a sheath core type, and a matrix-fibril type according to the distribution and arrangement of the components in the fiber. The side-by-side type composite fiber can be made into a fiber having curl by selecting components having different shrinkage ratios, and thus is used in chemical fiber-like wool.

3.1 Synthetic wool products The natural curling properties of wool are due to the bilateral structure of the cortex and cortical cells in the wool. In order to imitate the crimping characteristics of wool fibers, when spinning chemical fibers, two components with different shrinkage ratios can be used to produce side-by-side composite fibers having different shrinkage components on the same fiber cross-section, such as polyamide and Polyether, polyurethane polyether and polyacrylonitrile and other self-crimping side-by-side two-component composite fiber, the fiber has good curl durability, bulkiness, resilience, warmth retention, and the fabric feels smooth, The appearance is natural and elegant, and the wool-like effect is good.

4 flame retardant fiber

In order to mimic the non-flammable properties of wool fibers, wool-like chemical fibers can be made into flame retardant fibers.

4.1 Production of flame retardant fiber

Flame retardant fibers are generally produced by copolymerization or blending. The copolymerization method uses a monomer containing a flame retardant element (such as Cl, Br, P, etc.) to prepare a fiber-forming polymer having flame retardancy by copolymerization, and then spinning to obtain a flame-retardant fiber. In the blending method, a flame retardant is added to a spinning melt or a solution, and after mixing, spinning is performed to obtain a flame-retardant fiber.

4.2 Development of wool-like flame retardant fabric

At present, commonly used wool-like flame retardant fibers are: flame retardant polyester

5 microfiber

In Japan, fibers having a linear density of less than 0.3 dtex are referred to as ultrafine fibers. The microfiber has the advantages of soft hand feeling and comfortable wearing.

5.1 Production of microfiber

The superfine fibers mainly include two methods of direct spinning and composite spinning. The direct spinning method is to produce ultrafine fibers by a conventional melt spinning method. The composite spinning method is a method of spinning a composite fiber by a composite spinning technique, and then separating each component in the composite fiber by mechanical treatment or chemical treatment, or using a solvent to form a component of the island-in-the-sea composite fiber. Dissolved to obtain ultrafine fibers.