The so-called soft and comfortable handle of textiles is a subjective feeling obtained by touching the fabrics with your fingers. When people touch the fabrics, their fingers slide and rub between the fibers, the textile hand feeling and softness have a certain relationship with the coefficient of dynamic friction of the fibers. In addition, the fluffiness, plumpness and elasticity will also make the hand feeling of fabric soft. It shows that the hand feeling is related to the surface structure of the fiber. Take surfactant softeners for example. The operational principle of softeners is generally thought to be explained in two ways. It is easy for surfactants to have oriented adsorption on the surface of fibers. Although that surfactants are adsorbed on common solid surfaces decrease the surface tension, fiber surface area is difficult to expand. And textile fibers are made up of linear macromolecule with very large specific surface area and very elongated shape, whose molecular chain has good flexibility. After absorbing surfactants, the surface tension is decreased, which makes the fibers are easy to expand surface and elongate the length. So that the fabrics become fluffy, plump, elastic and soft. The stronger the adsorption of surfactant on the fiber surface and the greater the reduction of fiber surface tension, the soft effect is more obvious. Cationic surfactants can be strongly adsorbed on the fiber surface by electrostatic force (Most fibers have a negative surface charge). When the cationic group faces the fiber and the hydrophobic group faces the air, the effect of decreasing fiber surface tension is greater.
The oriented absorption of surfactants on fiber surface forms a thin film of hydrophobic groups neatly arranged outwards, which causes friction between fibers to occur between hydrophobic groups that slide against each other. Because of the oiliness of hydrophobic groups, the friction coefficient is greatly reduced. And the chain hydrophobic group is longer, it is slide more easily. The decrease of friction coefficient also decreases the flexural modulus and compressing force of fabrics, consequently influences the handle. At the same time, the decrease of friction coefficient makes it easy for the yarns to slide when the fabric is subjected to external forces, so that the stress is dispersed and the tearing strength is improved. Or during the working process, fibers subjected to strong force tend to revert to a relaxed state easily, making the handle soft. When people touch fibers, static friction coefficient plays an important role in the softness of fabric. But relatively speaking, the soft hand feeling of fibers is more related to the reduction of static friction coefficient.
Softening finishing agent generally refers to a compound that can be adsorbed on the fiber and smooth the surface of the fiber, increasing the softness of the fiber. At present, there are two types of commonly used softening agent, as surfactants and high-molecular softening agents. High-molecular softening agents mainly include silicone softeners and polyethylene emulsions.
Post time: Jan-08-2022