What is calcium stearate? Calcium stearate is an organic compound with a molecular formula of C36H70CaO4. It is a white powder, insoluble in water, and can be used as a waterproofing agent, lubricant, and plastic additive.
Calcium stearate is a calcium salt derived from calcium oxide and stearic acid that is commonly found in cosmetics, plastics, and food products. There are both pros and cons of using calcium stearate. Synthesis of calcium stearate
1. The synthesis of calcium stearate. The calcium chloride solution with a content of 1074kg/m3 (10°Bé) is added to the sodium stearate solution prepared above, and the metathesis reaction is carried out at about 65°C. The product calcium stearate is Precipitation separates out. Then it is filtered, washed with water, and dried at about 90°C to obtain the finished product.
2. Suspend 5.60g (0.1mol) calcium oxide in 300mL, 55℃ hot water. Then dissolve 51.3g of chemically pure stearic acid in 350mL of hot water at 70°C, add 0.75g of diethanolamine, and stir to emulsify it. The prepared stearic acid emulsion was gradually added to the calcium oxide suspension within 2h, and fully stirred, the formed white insoluble matter, namely calcium stearate, was filtered out and dried to obtain the product.
3. In the direct method, add a certain amount of stearic acid and CaO to a reaction pot equipped with a stirrer and a thermometer, heat it to melt, slowly add the catalyst H2O2 under constant stirring, and apply a vacuum to control the reaction temperature at 140-150°C. The reaction time is 1.5～2.0h. After the reaction is completed, the material is discharged, cooled, and crushed to obtain the product.
4. Metathesis method: Dissolve stearic acid in 20 times the mass of hot water, add saturated caustic soda solution, and carry out saponification reaction at about 75°C to generate dilute sodium stearate solution. Then the calcium chloride solution with a content of 1074kg/m3 was added to the sodium stearate solution, and the metathesis reaction was carried out at about 65℃, and the product calcium stearate was precipitated out. Then it is filtered, washed with water, and dried at about 90°C to obtain the finished product.
Calcium stearate application Calcium stearate can be used as a heat stabilizer for polyvinyl chloride, a lubricant for a variety of plastic processing, and a mold release agent. In hard products, mixing with basic lead salt and lead soap can increase the speed of gelation.
Calcium stearate is also used in non-toxic soft films and appliances such as food packaging and medical appliances. Calcium stearate can also be used as a halogen absorbent for polyethylene and polypropylene to eliminate the adverse effects of residual catalyst on color and stability.
In rubber processing, calcium stearate is used as a plasticizer, which can soften natural rubber and synthetic rubber, but has almost no effect on vulcanization. It is also used as a lubricant for polyolefin fibers and molding compounds, a thickening agent for grease, a waterproofing agent for textiles, a flattening agent for paints, and a plasticizer in the manufacture of plastic records. Used as halogen absorbent in polyethylene and polypropylene; lubricant and release agent for thermosetting plastics such as phenolic and amino; thickening agent for grease; waterproofing agent for waterproof fabric; flattening agent for paint and lubricant for pencil lead. Food-grade calcium stearate is used as an anticaking agent.
Calcium stearate is also used in pencil lead production, medicine, and the perfume industry.
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