Emulsified oil is composed of base oil and additives (emulsifier, rust inhibitor). Only when their proportions match properly, emulsified oil is more stable.
Base oil
Only when the base oil, corrosion inhibitor and emulsifier match properly, can the emulsified oil be stable. Different oil phases require different HLB values of emulsifiers, and different combinations of oil phases require different HLB values. Base oil is the carrier of corrosion inhibitor, and its viscosity affects the stability of emulsified oil. Low viscosity, easy to emulsify; But the viscosity is too low, the formation of protective oil film is too thin, is not conducive to rust prevention, so the viscosity of the base oil should be moderate.
additive
(1) Emulsifier. Emulsifier is the stabilizer of emulsion and a kind of surfactant. It can reduce the interfacial tension between insoluble liquids, so as to form emulsion. Surfactant molecules are usually composed of nonpolar, oil-philic (hydrophobic) parts of a hydrocarbon chain and polar, hydrophilic (oil-phobic) groups. These two parts are at opposite ends of the molecule, forming an asymmetric structure. Therefore, the surfactant molecule is an amphiphilic molecule with amphiphilic properties of both oil and water.
(2) Rust prevention agent. There are two main categories of rust prevention additives: water soluble rust prevention and oil soluble rust prevention. The process of rust prevention is mainly the process of the action of free alkali and water-soluble corrosion inhibitor, such as triethanolamine can interact with the metal, and generate an insoluble dense oxide film on the metal surface, preventing the electrochemical corrosion of the metal. But add triethanolamine must be appropriate, after excessive not only does not dissolve, but will affect emulsification, even demulsification.
(3) stabilizer. The role of stabilizer is not only to stabilize the oil phase, so that it is not stratified and transparent homogeneous, but also to stabilize the emulsion at room temperature and high temperature to prevent or reduce the stratification and oil extraction of the emulsion. The selected stabilizer is isopropyl alcohol, polyol (ethylene glycol), ethanol, high carbon alcohol, ditriethanolamine, phenylethanolamine and so on.
(4) In addition to the above additives, also include extreme pressure agent, alkali retention agent, fungicide, defoaming agent, complex agent, etc.
