The development of China’s chemical fiber imitation cotton has gone through three stages:
Phase 1It imitates cotton in terms of feel, gloss, and softness. Generally, combing, differential shrinkage, etc. are used to change the surface shape of the fiber, thereby changing the feel of the fiber;
The second stageis from the moisture regain rate The moisture-absorbing and sweat-wicking products currently on the market belong to the second generation of cotton-like imitations, which mainly use special-shaped cross-sections and then undergo post-finishing to achieve high moisture absorption and sweat-wicking effects;
The third generation of imitation cottonis currently underway Development of super imitation cotton products. The foundation of super-imitation cotton technology began with the fiber material design in the 1980s, emphasizing the integration of differentiated and functional series technologies and the mutual integration of polymerization, spinning, weaving, dyeing and finishing technologies. It is obviously different from the previous development of single differentiated technology or single functional products. Super cotton imitation products not only pursue the closeness to cotton fabrics (similarity) in fiber surface morphology and fabric style, but more importantly, they imitate cotton and super cotton in terms of fabric product functions. (Similar), especially in achieving ultra-cotton in terms of dynamic thermal and moisture comfort performance closely related to underwear and casual sportswear.
Imitation cotton The product positioning is to combine the excellent characteristics of cotton and polyester (PET) fibers to achieve the effect of imitating cotton, resembling cotton, and imitating cotton better than cotton.
In layman’s terms:Looks like cotton (visual), feels like cotton (tactile), wears like cotton (compatibility), super cotton (comfort), and is more convenient to use than cotton (washability) Wearability).
Scientifically speaking:Super imitation cotton products must ensure that the fibers have the excellent softness and warmth retention properties of cotton fibers, as well as the good mechanical properties, heat resistance, color fastness, and even anti-static and anti-static properties of polyester. Pilling, antibacterial, flame retardant, far infrared, and anti-UV functions.
This article interprets the performance indicators of super-cotton-like PET fiber from aspects such as gloss, feel, dyeability, and comfort.
1. Gloss
Cotton looks soft and mercerized, while pure PET fiber that has not been modified has a high gloss, looks very bright, and the fabric made is transparent. Therefore, in order to look like cotton, the luster of PET fiber must be controlled. Fiber is a translucent body, and its luster depends on both the surface reflected light and the transmitted light. The gloss of fiber is affected by factors such as fiber surface state, fiber cross-sectional shape, and fiber internal structure. Fibers with good macromolecular orientation. The internal structure is relatively uniform, the reflected light of the fiber is strong, and the luster is bright.
Therefore, the gloss can be controlled by adding inorganic particles to matt or adjusting the fiber cross-sectional shape, surface structure, etc. In order to make PET fiber close to the luster of cotton fiber, inorganic particles can be added during the polymerization process. The inorganic particles are dispersed in PET and destroy the crystallization and orientation of PET, thus making the fiber surface appear matt. The added amount of inorganic particles is generally 1.0%-2.0% by mass. The actual added amount can be adjusted during the production process according to product requirements.
2. Feel
In the microscope When looking at cotton fibers, you can see that the cross-section of cotton fibers isolor: #205867; –tt-darkmode-color: #6DB7CB;”>4.2 Wet transfer performance
The human body must rely on sweating to dissipate heat Only in this way can a thermal balance between heat production and heat dissipation be achieved. If a large amount of sweat vapor accumulates in the microclimate between clothing and skin and cannot be diffused or transferred to the environment in time, the human body will feel very uncomfortable. Therefore, the hygroscopicity and breathability of the fabric The properties are closely related to the moisture transfer performance of the fabric.
Cotton fabric is suitable for close-fitting wear and is skin-friendly. When the external environment is good, cotton fabric is very comfortable. Cotton fabric is very comfortable. Fiber is a hydrophilic fiber, and its hydrophilic properties include two aspects: hygroscopicity and water absorption of the fiber: the gas phase water is attracted or physically adsorbed by the fiber surface and internal chemical groups, which is called hygroscopicity, usually expressed by moisture regain. , the moisture regain of cotton fiber is about 8%; if the liquid water is diffused by the surface of the fiber or absorbed by the interior of the fiber, this characteristic is called water absorption.
There are two phases when moisture passes through fabrics: gas phase and liquid phase:
① Liquid water is transferred by the capillary action of the fabric. This transfer is also called Wicking transfer, that is, due to the existence of capillaries in the yarn and fiber structure of the fabric, liquid moisture (sweat secreted by the human body or natural water) can be transferred from one side of the fabric to the other through capillary action, thereby also transferring heat to the fabric the other side;
② Since sweat evaporates on the skin surface, when the partial pressure of water vapor in the air layer between the material on the side of the skin and the skin is greater than When there is a partial pressure of water vapor in the surrounding environment, the gas phase moisture mainly diffuses from the side with high partial pressure to the side with low partial pressure through the gaps between yarns and fibers in the fabric. This breathability is determined by the fabric structure and its porosity and thickness. This transmission method is the main way of evaporation and diffusion of sweat.
Cotton fiber has a good ability to manage gas phase water. It can absorb water discharged by the human body and keep the skin dry and comfortable, but it has poor management of liquid phase water. The ability is weak. When the external environment changes, the adjustment performance of cotton fiber is poor. Due to the high water retention rate of cotton fiber, when the human body sweats during extensive exercise, although the cotton fabric can absorb the water, it cannot discharge the water, causing the human body to be damp and stuffy. That is, the dehumidification and moisture conduction capabilities of cotton fiber are poor. The moisture conduction process of fabrics is essentially the phenomenon of liquid wicking and flowing in the capillary pores in the fabric, which is determined by the wetting and moisture conduction properties.
Super imitation The performance of cotton PET fiber will ultimately be reflected in the end product, and the fiber moisture regain is 1.0% -2.0% can meet the human body’s comfort requirements. Secondly, the fiber only needs to absorb water and moisten the surface, and does not need to absorb water into the interior of the fiber. The surface of cotton fiber contains a large number of hydroxyl groups, which combine with water molecules, so the water is not easily discharged, causing the human body to be damp and stuffy.
Super cotton-like PET fiber should also improve the gas phase The ability to regulate water and liquid phase water: First, the fiber must have hydrophilic properties. Only with hydrophilic properties can it absorb the water discharged by the human body; secondly, it must have good wettability. By adding polyhydroxyl-containing monomers during the polymerization process, the reaction rate is controlled to ensure that both ends of the polyhydroxyl monomer are connected to the PET macromolecular chain, and the remaining hydroxyl groups do not participate in the reaction, which can improve the hydrophilic properties of the PET fiber. In addition, the fiber surface state is changed by combining fine or ultra-fine denier, surface roughening, cross-section deformation, hollowing and other means to ensure that the fiber or fabric has a good wicking effect, so that water can be exported in time, so that the fiber has good Moisture-conducting properties keep the skin surface dry and warm. As shown in Figure 6 and Figure 7: The moisture regain rate of cotton-like hydrophilic PET fiber is lower than that of cotton fiber, but it is greatly improved compared with pure PET fiber. Secondly, the time for cotton-like hydrophilic fiber to absorb and release moisture to reach equilibrium is longer. Short, indicating that compared with cotton, cotton-like hydrophilic fibers have stronger dynamic real-time control capabilities.
