Introduction to Cleaning and Dispersing Agents in Lubricating Oil Additives

Introduction to Cleaning and Dispersing Agents in Lubricating Oil Additives

Lubricating oil additives, classified by function, can be divided into cleaning and dispersing agents, antioxidants and corrosion inhibitors, extreme pressure anti-wear agents, oiliness agents and friction modifiers, antioxidants and metal deactivators, viscosity index improvers, rust inhibitors, pour point depressants, and antifoaming agents.

The function of cleaning and dispersing agents is as follows:

Their main function is to keep the engine interior clean, ensuring that insoluble substances are in a colloidal suspension, preventing further formation of carbon deposits, varnish, or sludge. Specifically, their functions can be categorized into four aspects: acid neutralization, solubilization, dispersion, and cleaning.

1. Acid Neutralization: Cleaning and dispersing agents generally have a certain degree of alkalinity, some even highly alkaline. They can neutralize the organic and inorganic acids generated by the oxidation of lubricating oil, preventing further condensation and thus reducing varnish. They also prevent these acidic substances from corroding engine components.

2. Solubilizing effect: Detergents and dispersants are surfactants that solubilize solids or liquids that are normally insoluble in oil within micelle centers composed of 5-20 surfactant molecules. During use, they solubilize oxygen-containing compounds (hydroxyl, carbonyl, carboxyl groups), nitro compounds, and water into the micelles, forming colloids that prevent further oxidation and condensation, reducing the formation and accumulation of harmful deposits on engine parts.

3. Dispersing effect: They adsorb existing carbon deposits and varnish, dispersing them in the oil as a colloidal solution. This prevents these substances from further agglomerating into larger particles that adhere to engine parts or deposit as sludge.

4. Scrubbing effect: They wash away varnish and carbon deposits adsorbed on component surfaces, dispersing them in the oil and keeping the engine and metal surfaces clean.

The structure of detergent-dispersants is basically composed of three groups: lipophilic, polar, and hydrophilic. Due to differences in structure, the properties of detergent-dispersants vary. Generally speaking, detergents with ash additives have better detergency, while those without ash additives have superior dispersibility.

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