The commonly used additives for lithium-based grease are similar to other greases, but lithium-based grease uses a wider range of additives, and it has good compatibility with many additives. Commonly used additives mainly include antioxidants, metal surface passivators, preservatives, structural modifiers, extreme pressure antiwear agents, color stabilizers, and wire drawing enhancers.

    1. Antioxidant

    The commonly used antioxidants for lithium-based greases are:

    (1) Diphenylamine The molecular weight is 169.2, which is a commonly used antioxidant additive for lithium-based greases. The pure product is a white monoclinic needle crystal, and the industrial product is a yellow to brown crystal. Melting point 52.9 ℃, boiling point 302 ℃. Insoluble in water, soluble in alcohol, ether, benzene and other organic solvents. Industrial products can be refined with ethanol, which will gradually change color when exposed to light, and should be protected from light and sealed when stored. Experiments show that the antioxidant effect of diphenylamine in mineral oil lithium grease is better than that of phenyl-α-naphthylamine. The optimum dosage is 0.1%~1.0%.

    (2) Benzyl-α-naphthylamine, also known as anti-aging agent A, the unified code of petroleum additives is T531. Colorless flaky crystals, which gradually turn yellow or purple when exposed to sunlight or air. poisonous! The relative density is 1.16~1.17, and the melting point is 62℃. Insoluble in water, soluble in ethanol, ether, benzene and other organic solvents. It is mainly used as an antioxidant for rubber products, and is also one of the most effective oxidation inhibitors for grease. It is commonly used in lithium-based greases such as synthetic ester oils, and the operating temperature can reach 150 °C. The addition amount is generally 0.1%~1.0%.

    (3) Phenyl-β-naphthylamine, also known as anti-aging agent. The pure product is light gray needle-like crystal, which gradually turns gray-red when exposed to air or sunlight. The relative density is 1.18~1.19, and the melting point is 106~108℃. Insoluble in water, soluble in ethanol, carbon tetrachloride, easily soluble in organic solvents such as acetone, ethyl acetate, methyl chloride, benzene and carbon disulfide. Its properties are basically the same as phenyl-α-naphthylamine, and it is an important general-purpose antioxidant.

    (4) 2,6-di-tert-butyl-p-cresol The unified code for petroleum additives is T501. The pure product is a white crystal, which turns yellow and gradually darkens when exposed to light. The relative density is 1.048, the melting point is 70℃, and the boiling point is 257~265℃. Insoluble in water and dilute alkali solution, soluble in benzene, toluene, alcohol, ketone, carbon tetrachloride, ethyl acetate and gasoline. The low-temperature antioxidant effect of this antioxidant is better. If this antioxidant is used in combination with other antioxidants, such as diisooctyl diphenylamine, its antioxidant effect will be increased several times.

    Antioxidants are in the order of antioxidant effect in lithium 12-hydroxystearate greases: diphenylamine>phenyc-α-naphthylamine>zinc diamyldithiocarbamate.

    2. Anti-rust agent

    Commonly used lithium-based grease rust inhibitors are:

    T701 barium petroleum sulfonate, T704 zinc naphthenate, T705 barium dinonylnaphthalene petroleum sulfonate, T706 benzotriazole.

    T701, T704 and T705 have good effect on the rust prevention of copper, and the derivative of benzotriazole, octadecylamine salt, also has a good effect on rust prevention.

    3. Extreme pressure and anti-wear additives

    Due to the development of modern technology, the lubrication of many equipment in the iron and steel industry and heavy machinery industry is in the state of boundary lubrication. The lubrication of the working parts of the machine needs to use high-quality extreme pressure grease to meet the lubrication requirements. Lithium-based grease is a general-purpose grease with good compatibility with extreme pressure and anti-wear additives. After adding extreme pressure and anti-wear additives, extreme pressure lithium-based grease with excellent performance can be prepared.

    The effect of extreme pressure additives is roughly the same. Phosphorus compounds can effectively improve the anti-wear properties of grease, while sulfur and chlorine compounds can effectively improve the load resistance of grease. and sulfur compounds, both extreme pressure and anti-wear properties. In order to improve the antiwear and extreme pressure properties of lubricating batches, two or more extreme pressure antiwear additives can be used in combination.

    4. Adhesive and various drawing agents (structural improvement agent)

    In recent years, many special lithium-based greases have been added with ethylene-propylene copolymers, polyacrylates, polyisobutylene and other polymers to improve the mechanical stability of the grease and increase the adhesion and drawability of the grease.

    5. Filler (filler)

    Fillers often refer to finely dispersed solid substances, which also have the characteristics of solid lubricants. The purpose of adding fillers is to reinforce the lubricating film of the basic grease under heavy load, vibration, shock load or high temperature. There are many types of fillers. At present, the main ones used in lithium-based grease are molybdenum disulfide, graphite, boron nitride, MCA (melamine cyanurate), PTFE (polytetrafluoroethylene), etc.