I.Overview

  In the early stage, the widely used detergent dispersants in internal combustion engine oil are metallic sulfonates, alkyl phenols, phosphonates and alkyl salicylate, which are called metal detergent dispersants. Subsequently developed a metal-free additive, it has excellent dispersion properties, in order to distinguish from the former, people called it ash-free powder. Due to the outstanding role of ash-free dispersant in internal combustion engine oil, the usage amount is more and more, and its main function is dispersion, so it has been clearly divided into two categories of metal cleaning dispersant and dispersant, dispersant is also one of the five modern lubricant additives (cleaning agent, dispersant, viscosity index improver, anti-wear additives and antioxidants).

  The development of Ashless Dispersant is indivisible from the development of modern automobile industry. In modern times, the rapid increase of cars has resulted in the aggravation of environmental pollution and urban traffic congestion. To reduce air pollution, positive pressure intake and exhaust (PCV) systems are commonly used, which carry acid into the crankcase and thus require higher performance of the internal combustion engine oil. Traffic congestion, so that the city driving cars often run at a low speed and stop to open, in this case the car crankcase oil temperature is low, so that fuel hydrocarbon and moisture (moisture) is not easy to discharge from the lubrication, so that the paint film and sludge sediment has increased. It is because of the increase in short-distance vehicles and the use of PCVS that the tendency to form paint and sludge deposits in lubricating oil has increased. A large amount of water vapor is partially condensed to produce a large amount of emulsified oil sludge, which causes the blockage of pipeline and filter screen, and seriously affects the normal use of crankcase oil. There is an urgent need to develop an effective additive for this kind of low temperature sludge because the previous metal cleaning agents such as phosphonate, sulfonate and phenol salt have little effect. In 1955, DuPont Company of the United States developed a new type of polymer dispersing additive, because it does not contain metal, no ash after combustion, so called ash free additive. This kind of ash free agent improved the low temperature sludge problem to a certain extent, but it was not ideal until the 1960s, the emergence of non-polymerized succinimide ash free agent to solve the low temperature sludge problem satisfactorily. However, with the continuous improvement of engine performance, the so-called "BlackSludge" problem emerged in the 1980s, which required the combustion engine oil to have excellent high temperature cleanliness and dispersity. In order to meet this requirement, a new type of dispersant with high molecular weight came into being and has now become the main additive for preparing high-grade combustion engine oil.

II. Performance of dispersant

  At present, polyamine based succinimide is the main dispersant, and its usage accounts for more than 80% of the total dispersant. Its chemical structure is composed of oleophilic group, polar group and connecting part. Such a structure is easy to form micelles in lubricating oil, ensuring that it has a strong solubilization effect on the initial oxidation products of liquid, as well as a good colloidal dispersion effect on solid particles such as carbon accumulation and soot. Therefore, it can effectively ensure the low temperature dispersion of internal combustion engine oil, especially effectively solve the low temperature oil sludge problem of gasoline oil. So the gasoline oil with dispersant, running for a long time after the oil change, the crankcase oil sludge is reduced, but it also improves the dispersion and solubilization of soot and lubricating oil oxidation products produced by high temperature oxidation, especially after the synergistic effect with metal cleaning agent compound, not only improves the quality of lubricating oil, but also reduces the amount of additives. Because of its advantages succinimide ash free dispersible has been rapidly developed and applied. The main function of dispersant in oil is dispersion and solubilization.

Dispersants produced by Liaoning Hongyi Chemical Co., Ltd. mainly include Mono-Succinimide HY151 (Mono-Succinimide), Bis-Succinimide HY154 (BIS-Succinimide), polysuccinimide HY155 (Poly-Succinimide) and high molecular weight dispersant HY161 (High Molecular Weight Dispersant).

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