There are many surface active agents in lubricant additives, such as detergents, anti-foam additives, antirust additives, and some of them have multiple functions.
The good surface active agent should have the following characteristics:
Resistance to hard water: it’s a method to measure the emulsifiers’ resistance to hard water. Generally speaking, the traditional anion has a poor performance in this aspect; the cation is displacing them.
Foams: in the lubricant oil, it’s widely believed that the less foam, the better. Therefore, we need to choose different types of emulsifiers and reduce the foam as much as possible.
Biological stability: it’s the performance requirements of the emulsifier. In the long term, if the emulsifiers are eroded by bacteria, it’s harmful to the lubricant oil.
The increasing development of environmental protection has put higher demands for lubricant additives, and dealing with the recycled waste oil and industrial wastewater is an important measure of controlling lubricant oil pollution.
Detergent dispersant additive
The detergent additive in the engine oil can keep the inner engine clean, and inhibit the formation of absorbed ink, accumulate carbon, oil, and dirt.
The commonly used detergent additives are Petroleum sulfonate, alkylphenate, salicylate, and polyisobutylene succinimide, and they all have a wide application.
The main mechanism is making the particles and non-soluble substances distribute uniformly by means of diversification, adsorption, and emulsification, and form a micellar solution, which is helpful to prevent them from adhering, depositing, or blocking the oil passage and filter screen.
Antifoam additive:
Some oil-soluble surface active agents can be used as a lubricant anti-foam additive. The commonly used defoamers are divided into 3 types: anti-foam additives with silicon, non-silicon antifoam additives, and compound antifoam additives. The main function is to prevent the formation of air bubbles in the lubricating oil or to remove the formed air bubbles as soon as possible.
The common silicon polymer is polymethylsiloxane defoamer for lubricants; a non-silicon antifoam additive is a mixture of synthetic hydrocarbons and polymer. The compound defoamers are usually a combination of the above 2 types of anti-foaming agents, having both advantages.
Anti-rust additives
Rust preventive additive can be used as the surface active agent, which is mainly water in oil. The common antirust additives are carboxylic acids and their salts, alkylbenzene sulfonates, nitrogen-containing amphiphilic molecules, and some phosphorus-containing compounds.
The surface active additive also uses the lubricant emulsifier; it’s mainly used to reduce the tension between the water and oil surfaces, making them mix together and form a uniform dispersant system.
Emulsifiers and antirust additives are the important role in lubricant oil.
At present, the surface active agent is mainly used to promote the uniform spread of the oil, biodegradation, and dealing with wasted oil and water.
