Metal stearates are a class of multifunctional additives used in many articles and can bring many benefits to polymer products. We can divide these benefits into three main areas:

Acid neutralizers in polyolefins have a direct contribution to the color stability and corrosion resistance of polyolefins;

Lubrication/processing aids Improve the processability of polyolefins, polyamides, styrenics and rubbers during extrusion (film, fiber, profiling, etc.) and compression molding;

Release properties For thermoplastics, rubber and thermosets such as polyurethane foam and unsaturated polyester.

Common Stearates

1. Calcium Stearate

Calcium stearate: softens around 125°C and begins to melt around 145°C until it becomes completely fluid. Calcium stearate, recognized as physiologically safe, is insoluble in most solvents. On heating, they are sparingly soluble in aromatic compounds, chlorinated hydrocarbons or in vegetable, mineral or paraffin oils. It is used as heat stabilizer for polyvinyl chloride, lubricant for various plastics processing, mold release agent, etc. In hard products, it can improve the gelation speed when combined with basic lead salt and lead soap.

2. Zinc Stearate

The melting point is about 120℃, and the melting range is small. After melting, it becomes a liquid with low viscosity. The state is divided into white turbid liquid and clear transparent liquid. Product classification can be divided into solid zinc stearate and water-based zinc stearate. Their main field of application is the plastics and rubber industry, where they are used as release agents and lubricants due to their good compatibility

3. Magnesium Stearate

It begins to soften at around 90°C, begins to melt at 95°C to 97°C and completely melts at around 105°C. Mainly used as lubricant, anti-sticking agent and glidant. It is especially suitable for the granulation of oil and extract medicines, and the granules made have good fluidity and compressibility. Used as a glidant in direct compression. It can also be used as a filter aid, a clarifying agent and a foaming agent, as well as a suspending agent and thickening agent for liquid preparations