In the lubricant industry, the variety of base oils is constantly expanding, the performance is constantly improving, the structure and variety of additives are constantly innovating, the process is constantly improving, the functions are becoming increasingly diversified, the variety of composite agents is also becoming more and more perfect, the quality is getting better, and the blending equipment is becoming more and more advanced. These directly lead to the technological progress and product quality improvement of our entire lubricant industry. At the same time, it also leads to fierce competition in the product market. Therefore, in the process of increasingly strong product quality, there are no shortage of inferior and inferior products.

A little more lubrication leads to less friction. Lubricating oil will experience certain shear stress between friction pairs. Among the three major oil products, internal combustion engine oil, hydraulic oil, and gear oil, in terms of their shear rates, if the internal combustion engine oil is on the order of 10-4/second, hydraulic oil is 10-6/second, gear oil is 10-8/second, and gear oil is an extreme pressure oil. Therefore, the viscosity of gear oil is relatively high to effectively maintain a sufficient lubricating oil film. Bright oil is a high viscosity base oil, commonly found in 150BS, as well as 90BS, 120BS, and 250BS. Its viscosity can reach 300-400 and 30mm2/s at 40 ℃ and 100 ℃, respectively. When it comes to industrial gear oils such as 90, 140, 460, 680, or even 1000, using only mineral base oils is helpless. At this time, synthetic oils or thickeners are needed to achieve our goals. Some special varieties of synthetic base oils have a viscosity of up to 20000 mm2/s at 40 ℃, which can solve the problem. However, sometimes the cost of the product is difficult for ordinary people to afford. Another approach is to use thickening agents, so the question is: what kind of thickening agent should be used? How to use it?

Ethylene propylene copolymer (OCP), polyisobutene (PIB), hydrogenated styrene isoprene (PSEP), and of course, poly (methyl methacrylate) (PMA) are also indispensable. In fact, most of the thickening agents and pour point depressants in lubricants are closely related to the rubber, plastic, and resin industries. For example, PMA, if it is poly (methyl methacrylate) (PMMA), it is organic glass. Interdisciplinary emerging disciplines, you and I are directly involved!

As for gear oil, the use of thickeners should consider several issues: ① thickening ability; ② Shear stability; ③ Thermal oxidation stability; ④ The contribution of thickening agents to oil film thickness. Note that thickening ability and oil film thickness are two separate concepts. The thickening ability and shear stability are both related to the polymerization degree of the polymer. The intuitive representation method is the average molecular weight, which is also related to the distribution state of molecular weight. The intuitive representation method is the size of the molecular weight distribution range. In short, thickening ability and shear stability have exactly opposite requirements for molecular weight size; The thermal oxidation stability is related to the molecular structure of the polymer; And the thickening ability and oil film thickness are a relative contradiction. At the same time, thickening agents and pour point depressants are also intricately linked. Therefore, when it comes to seemingly simple but often inseparable thickening agents, there is no shortage of knowledge and experience involved. The so-called simplicity rather than simplicity? Let's talk about it next time.