Hyaluronic acid (HA) molecule contains a large number of hydroxyl groups and other polar groups, which can absorb water about 1000 times its own weight like a “molecular sponge”. Data shows that HA has relatively high moisture absorption under low relative humidity (33%), and relatively low moisture absorption under high relative humidity (75%). This unique property adapts to the requirements of the skin in different seasons and different humidity environments, so it is known as an ideal natural moisturizing factor. In recent years, with the improvement of production technology and the popularization of HA skin care applications, some innovative companies have begun to explore the preparation methods of HA fabrics.

Padding

The padding method is a processing method that uses a finishing agent containing HA to treat the fabric by padding. The specific steps are to soak the fabric in the finishing solution for a period of time and then take it out, and then pass it through squeezing and drying to finally fix the HA on the fabric. Studies have shown that adding HA in the finishing process of nylon warp knitted fabrics has little effect on the color and color fastness of the fabric, and the fabric treated with HA has a certain moisturizing effect. If the knitted fabric is processed to a fiber linear density of less than 0.13 dtex, the binding force of HA and fiber can be improved, and the moisture retention ability of the fabric can be avoided due to washing and other factors. In addition, many patents show that the padding method can also be used for the finishing of cotton, silk, nylon/spandex blends and other fabrics. The addition of HA makes the fabric soft and comfortable, and has the function of moisturizing and skin care.

Microencapsulation

The microcapsule method is a method of wrapping HA in microcapsules with a film-forming material, and then fixing the microcapsules on the fabric fibers. When the fabric is in contact with the skin, the microcapsules burst after friction and squeezing, and release HA, exerts skin care effect. HA is a water-soluble substance, which will be lost a lot during the washing process. The microencapsulation treatment will greatly increase the retention of HA on the fabric and improve the functional durability of the fabric. Beijing Jiershuang High-Tech Co., Ltd. made HA into nano-microcapsules and applied them to fabrics, and the moisture regain rate of the fabrics reached more than 16%. Wu Xiuying prepared a moisturizing microcapsule containing HA, and fixed it on thin polyester and pure cotton fabrics through low-temperature cross-linking resin and low-temperature fixing technology to obtain long-lasting moisture retention of the fabric.

Coating method

Coating method refers to a method of forming a HA-containing film on the surface of the fabric, and achieving skin care effect by fully contacting the fabric with the skin during the wearing process. For example, layer-by-layer electrostatic self-assembly technology is used to alternately deposit chitosan cation assembly system and HA anion assembly system on the surface of cotton fabric fibers. This method is relatively simple, but the effect of the prepared skin care fabric may be lost after multiple washings.

Fiber method

The fiber method is a method of adding HA in the fiber polymerization stage or spinning dope, and then spinning. This method makes HA not only exist on the surface of the fiber, but also uniformly distributed inside the fiber, with good durability. MILAŠIUS R et al. used electrospinning technology to distribute HA in the form of droplets in nanofibers. Experiments have shown that HA remains even after soaking in 95 ℃ hot water. HA is a polymer long-chain structure, and the violent reaction environment during the spinning process may cause damage to its molecular structure. Therefore, some researchers have pretreated HA to protect it, such as preparing HA and gold into nanoparticles, and then uniformly dispersing them in Among polyamide fibers, cosmetic textile fibers with high durability and effectiveness can be obtained.