The composite calcium sulfonate-based thickening system […]
The composite calcium sulfonate-based thickening system mainly consists of two parts.
One part is non-Newtonian calcium sulfonate and the other part is complex calcium soap. They are both physically mixed and chemically associated in the system and are a relatively complex compound system.
The primary thickening agent in the complex calcium sulfonate-based thickening system is a non-Newtonian calcium alkylbenzene sulfonate which is converted from the high base number calcium alkylbenzene sulfonate of Newtonian. The high base number calcium alkylbenzene sulfonate of Newtonian may have a TBN value of 300 or more. The high base calcium sulfonate is composed of calcium alkylbenzenesulfonate normal salt and calcium carbonate basic salt. The calcium carbonate microparticles are generally less than 100 Å, and are encapsulated by calcium sulfonate molecules to form stable colloidal particles dissolved in oil. This oil-soluble, high base calcium sulfonate has a transparent and uniform appearance. Its chemical formula is: [R-SO3]2Ca(CaCO3)n, where R is aryl or alkyl, and the value of n can be as high as 40.
Through the action of the promoter, the high-basic calcium sulfonate is converted from Newtonian to non-Newtonian. The calcium carbonate in the system mainly exists in the form of calcite crystals, and rapidly aggregates into large particles under the action of water. These particles are spherical in shape and form a three-dimensional accumulation structure by the interaction between molecules. With this spherical structure as the center, calcium sulfonate is adsorbed on the surface, and since the hydrocarbon-based end of calcium sulfonate is well dissolved in oil, This enclosed calcium carbonate stereostructure is well dispersed in the system to hold a significant portion of the base oil therein. This non-Newtonian, high base calcium sulfonate has thixotropic properties and acts as a thickener for greases. The way calcite adheres to the friction surface provides excellent resistance to abrasion, extreme pressure and rust.
The process of converting high-basic calcium sulfonate from Newtonian to non-Newtonian is an endothermic process. It is obvious during the test that the temperature of the system is stable during the conversion process. In order to ensure complete conversion, it should be heated continuously. .
The composite calcium soap is another thickening agent of the calcium sulfonate grease. The calcium soap fiber is a carboxyl group to a carboxyl group, and the hydrocarbon group is arranged in a hydrocarbon group. The structure is in the form of a velvet group in the system, and they are puffed in oil. A part of the base oil is adsorbed therein like a sponge. In order to be fully compounded, it should be properly insulated when the maximum refining temperature is reached.
The composite calcium sulfonate grease relies on the three-dimensional accumulation structure of calcium carbonate, the fiber structure of the composite calcium soap, and the hydrogen bond association structure of calcium acetate and calcium sulfonate to thicken the base oil into a grease.