What is zinc stearate and what does it do
- Mingpai
- 2024-05-31 14:03:34
Stearic acid zinc salt, commonly known as zinc stearate, is a white, fine, and softly fatty-smelling powder with the chemical formula C36H70O4Zn. Derived from the reaction between stearic acid and zinc oxide, it is insoluble in water, ethanol, and ether but can be dissolved in hot ethanol, turpentine, benzene, and other organic solvents. Characterized by its hygroscopicity, lubricating properties, and good adhesion to skin, zinc stearate is a low-toxicity, environmentally friendly chemical compound.
The primary functions and applications of zinc stearate include:
Plastics Industry: It serves as a lubricant and release agent for styrene resins, phenolic resins, amino resins, enhancing flow properties during processing and the surface finish of the final product while facilitating demolding.
Rubber Industry: In rubber compounds, it acts as a vulcanization activator and softener, improving processability and physical properties of the rubber.
PVC Stabilizer: It is employed as a non-toxic heat stabilizer for polyvinyl chloride (PVC), inhibiting initial color change and offering excellent lubrication, although its thermal stability is limited and may catalyze PVC degradation. Thus, it's typically combined with other metal soaps such as calcium and barium soaps, particularly in soft PVC products.
Paints and Coatings: Within paint formulations, it functions as a matting agent and additive, contributing to a smooth finish and enhancing sanding properties.
Water-Based Systems: In waterborne coatings, it improves slip and sandability, and is a crucial promoter in foam products.
Personal Care and Pharmaceuticals: Thanks to its skin compatibility, zinc stearate finds use in certain cosmetics and personal care products, as well as a lubricating protectant for minor skin irritations.
Miscellaneous Uses: It is also used as a finishing agent in textiles for added luster and as a food additive (within regulated limits) to improve texture and mouthfeel of foods.
In summary, zinc stearate, due to its unique physicochemical properties, plays a significant role across various industries, prominently in plastics, rubber, and coating sectors.
