It is understood that stearic acid is a white flake, bead or block solid at room temperature. It is composed of saturated fatty acids mainly C16 and C18. It is insoluble in water, slightly soluble in benzene and carbon disulfide, easily soluble in hot ethanol, non-toxic and tasteless, and has the general chemical properties of organic carboxylic acids. Stearic acid is a fatty acid widely found in nature. Almost all oils contain stearic acid in varying amounts. The content is higher in animal fats. For example, the content in butter can reach 24%, and in vegetable oils it is less. , tea oil is 0.8%, palm oil is 6%, but the content of cocoa butter is as high as 34%. There are two main production methods for industrial stearic acid: fractionation method and pressing method. A decomposing agent is added to the hardened oil, and then it is hydrolyzed to obtain crude fatty acids, which are then washed, distilled, and decolorized to obtain the finished product, while glycerol is produced as a by-product.
Stearic acid has multiple functions as lubricant, plasticizer, dispersant, stabilizer, antioxidant and flame retardant in plastic fillers. It can improve the processing performance and physical properties of plastics. , weather resistance, corrosion resistance and combustion performance, improving the quality and performance of plastic products.
The specific functions of stearic acid in plastic fillers are as follows:
1. Lubricant: Stearic acid can be used as a lubricant for plastic fillers. , During the plastic processing process, the friction between the filler and the plastic matrix will cause the generation of heat, which will affect the processing performance of the plastic. The addition of stearic acid can reduce the friction between the filler and the matrix, reduce the heat generation of the plastic, and improve the fluidity and processability of the plastic. In addition, stearic acid can also reduce the friction between the filler and the mold, reduce mold wear, and extend the service life of the mold.
2. Plasticizing effect: Fillers in plastics play a role in enhancing the strength of the material and improving the physical properties of the plastic. The addition of stearic acid can enhance the compatibility between the filler and the plastic matrix, making the filler better dispersed in the plastic and improving the filling effect of the filler. By increasing the filler, it is better dispersed in the plastic and the filling effect of the filler is improved. By increasing the content of fillers and improving the dispersion of fillers, the strength and hardness of plastics can be effectively improved, and the toughness and heat resistance of plastics can be increased.
3. Improve the dispersion and stability of fillers: The dispersion and stability of fillers in plastics are crucial to the performance and quality of plastic products. As a surfactant, stearic acid can form a thin film on the surface of fillers, improve the aggregation and precipitation of fillers, and improve the mechanical properties and appearance quality of plastic products.
4. Improve the weather resistance and corrosion resistance of the filler: When the filler in plastic products is exposed to the external environment, it is easily affected by sunlight, oxygen, moisture, chemicals, etc., resulting in plastic The performance of the product decreases. The addition of stearic acid can form a protective film to block erosion from the external environment, improve the weather resistance and corrosion resistance of the filler, and extend the service life of plastic products.
5. Improve the combustion performance of fillers: The combustion performance of fillers in plastic products has an important impact on the safety and environmental protection of plastic products. The addition of stearic acid can improve the burning performance of fillers, reduce the burning speed and flame diffusivity of plastic products, reduce the generation of harmful gases and smoke, and improve the flame retardant properties of plastic products.
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