Texture agent is a chemical used to adjust the tactile sensation of leather and other products. Hand feel agents can give products a smooth, soft, astringent, silky, cotton, linen, velvet, oil, wax, stickiness, etc. As the main components of the feel agent are insoluble in water, the leather feel agent can be divided into solvent type and lotion type according to the product state; According to the main active ingredients, it can be divided into wax hand feel agents, organic silicon hand feel agents, and silicon wax composite hand feel agents; Common application effects include wax sensitizers, lubricants, softeners, and multifunctional hand feel agents.
Wax sensitizer is a wax lotion with natural wax or synthetic wax as raw material or an organic solvent dispersion with wax as the main component. Smoothing agent can give the coating a comfortable and smooth feel, usually silicone lotion, wax lotion with high melting point and high hardness and their compounds. Softeners can improve the softness of leather. Softeners are often classified according to their charged state into anionic, cationic, nonionic, and amphoteric softeners; Most softeners are composed of organosilicon and surfactants.
Among the hand feel agents, organic silicon hand feel agents have the best effect, the most varieties, the widest application, and the fastest development. Leather treated with organic silicon hand feel agents not only maintains elasticity, fullness, breathability, and hygiene performance, but also improves hand feel and softness. After finishing, it dries quickly and is not easily hardened or brittle. The surface of leather has good stability to water and chemicals, and is not easily deformed, which helps reduce the difference in leather parts. Organosilicon is also the basis for preparing multifunctional hand feel agents, so the preparation of organosilicon hand feel agents has received widespread attention.
Application methods and characteristics of silicone hand feel agent:
Organic silicone hand feel agent can be used for leather bottom, middle, and top coating. The lotion organosilicon hand feel agent can be directly used for top coating after being diluted with water. The organosilicon handle agent has good compatibility with pigment paste, acrylic acid lotion or polyurethane lotion. However, the introduction of organic silicone hand feel agents in polyurethane can reduce the tensile strength of the film. Therefore, the amount of additives should be minimized as much as possible while achieving specific performance, such as achieving appropriate smoothness. In general, an increase in the amount of hand feel agent used will affect the adhesion strength and resistance to dry and wet rubbing of the coating. Cationic silicone lotion can be considered to use "sandwich" finishing method for finishing.
Future research directions for hand feel agents:
(1) The organic silicon conventional lotion was modified to synthesize a stable and new characteristic active organic silicon lotion for leather feel agent. Organic silicon softeners are widely used in the textile industry, so research can first be conducted on the use of soft and smooth agents as leather hand feel agents in textile dyeing and finishing auxiliaries. At present, the softening finishing of white or light colored fabrics mainly uses epoxy based silicone lotion. The epoxy based silicone lotion can be used alone or in combination with other modified silicone lotion to make the finished fabric soft, smooth and free from yellowing. Some of them can be considered as leather feel agent after slightly adjusting.
(2) The organosilicon lotion containing a variety of active groups is developed as a leather feel agent.
(3) Develop environmentally friendly green chemicals. The production process of solvent based hand feel agents is simple, with good stability and application effects, but they are toxic and should be eliminated or new technologies should be adopted to avoid their harm.
(4) A single performance hand feel agent can no longer meet the requirements for preparing high-end leather. The serialization, high-end, and multifunctional development of hand feel agents to provide different hand feel styles (such as smoothness, oiliness, waxiness, or other composite hand feel) is the future direction of leather hand feel agents, such as introducing phthalimide groups to improve anti fouling and softness, introducing organic fluorine to improve oil repellency, anti fouling, and anti-static properties. For the development of leather feel agents, focus on high-end and high efficiency, and strive for export; In China, research and development of new products with high usage, wide application, low cost, and good benefits should be conducted to meet market demand.
