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Chemical Additives in Rust Preventive Oil

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Update time : 2019-10-16 14:45:35

Antirust grease is an oil which is composed of mineral oils and fats, is added with various oil-soluble corrosion inhibitors and additives, and has an antirust effect on metal products, and is called antirust grease. It consists of oil-soluble corrosion inhibitor, base oil, and auxiliary additives. This article describes the main chemical additives in rust preventive oils.

 

1. Preparation of antirust oil material - aluminum bis-stearate

Aluminum stearate is commonly known as brushed butter or glass butter. It is a white powder or solid particles at room temperature, insoluble in water, and has less solubility in mineral oil, but it can significantly thicken mineral oil. In the preparation process, aluminum monostearate, aluminum stearate, and aluminum tristearate are obtained according to the amount of the aluminum salt. Among them, aluminum bis-stearate has the best rust resistance. The industrial product aluminum stearate is a mixture of three aluminum stearate and a small amount of aluminum oleate soap. Aluminum stearate has excellent resistance to damp heat, salt spray, and atmospheric resistance. It has an antirust effect on ferrous metals, copper, and aluminum, but water film and sweat displacement ability and saltwater impregnation ability are poor. It is used to prepare grease type antirust oil, which is suitable for measuring and antirust of measuring tools and cutting tools.

 

2. Antioxidants in antirust oil

During storage and use, rust preventive oil usually undergoes free radical chain reaction due to the action of light, heat, and metal, which causes the oil to precipitate or gel and deteriorate. For this reason, it is usually necessary to prevent or slow down. Anti-rust oil oxidative deterioration additive - antioxidant. Antioxidants commonly used in antirust oils are phenols and amines.

1. 2,6-di-tert-butyl-p-cresol: it is an alkylation reaction of isobutylene and p-cresol under the catalysis of concentrated sulfuric acid, and then refined by neutralization. It is a free radical reaction terminator. Codenamed T501, also known as 264. It is white or yellowish crystal at room temperature, and the usual amount in antirust oil is 0.3%.

2. Diphenylamine: It is a free radical reaction terminator which is obtained by the condensation reaction of aniline under the catalysis of anhydrous aluminum trichloride, followed by salting out, neutralization, distillation, and crystallization. At room temperature, it is colorless to light gray crystal, flammable, aromatic, and it is grayish-black after exposure. It is soluble in mineral oil, ether, benzene, glacial acetic acid, and carbon disulfide.

3. Butyl octyl dithiophosphate: It is based on isooctyl alcohol, n-butanol, phosphorus pentoxide and zinc oxide, and 150 SN neutral oil as diluent, sulfur phosphating and saponification reaction. It is obtained by vacuum dewatering and filtration. The code T202 is a peroxidation decomposing agent with anti-wear and anti-corrosion properties. It has excellent oxidation resistance at higher temperatures and can be used as lubricating rust. The oil is usually used in an amount of 0.5%.

 

3. Auxiliary materials for antirust oil

To make the antirust oil meet the requirements of different antirust objects, different use processes, and storage, in addition to the oil-soluble corrosion inhibitor and some of the above auxiliary additives, some special additives are sometimes added. 1. Defoamer: For equipment using antirust oil or lubricated antirust grease, when the machine is running, the air layer in contact with the oil is vibrated, and some of it is brought into the oil, and the formed small bubbles are difficult to disappear. The defoamer molecule can quickly enter the interface between the bubble and the oil, destroying the mechanical balance of the interface liquid film, and achieving the purpose of destroying the foam or suppressing the foam. Methyl silicone oil is a commonly used defoamer. 2. Extreme pressure additive: For the use of antirust oil equipment, when the machine is running, the parts of the metal surface that contact each other sometimes generate high pressure and a large amount of friction heat, which causes the oil film between the metals to be damaged, resulting in dangerous parts. Worn or sintered. Under the above conditions, the extreme pressure additive can form a chemical reaction film with a lower melting point and a smaller shear strength with the metal surface, instead of direct friction between the metals, reducing frictional resistance and preventing scratching and sintering of the metal surface. Commonly used extreme pressure agents are boron-containing compounds, sulfur phosphorus compounds, chlorides, and certain high molecular compounds. 3. Cosolvent: It is a class of compounds that can increase the solubility of certain additives, which are poorly soluble in rust preventive oil and make the additive stably present in the rust preventive oil system. Commonly used cosolvents are dibutyl phthalate, dioctyl phthalate, ethanol, and butanol.

 

4. Antirust agent commonly used in the antirust agent zinc naphthenate

The antirust agent widely used in antirust oil, zinc naphthenate, is a by-product sodium naphthenate obtained by crude oil in the chemical washing process, which is obtained by metathesis reaction of zinc sulfate. It is brownish yellow to dark brown viscous liquid at room temperature. Zinc naphthenate is soluble in mineral oil and has a specific solubility effect on potent polarity corrosion inhibitors. The anti-moisture result of ferrous metal is obvious; the neutralization and replacement of sweat, the antirust effect on copper, brass, and bronze is not significant, the anti-overlap property is not ideal, and the salt spray resistance is weak. Used in combination with petroleum sulfonate or bismuthonaphthalene sulfonate to enhance the antirust effect on cast iron. The addition of zinc naphthenate increases the acid value of the base oil. When the amount is 1%, the acid value can be increased by 1.0-1.2 mgKOH/g, and the mineral oil is accelerated, and the oxidation is faster when heated. Used in ferrous metal, non-ferrous metal process, or warehouse for short-term rust prevention. An oil is containing a large amount of zinc naphthenate, avoiding prolonged heating and preventing oxidation.

 

5. Preparation of decyl succinic acid for rust preventive oil

The preparation of antirust oil is commonly used as dodecyl succinic acid, which belongs to an alkenyl succinic acid corrosion inhibitor. It is brownish yellow and brownish red transparent viscous liquid at room temperature. It is not steam turbine oil, soluble in water, soluble in alcohol, and mineral oil. Dodecyl succinic acid has a high solubility in mineral oil. Because it contains two carboxyl groups at the same end of the molecule, it can strongly adsorb on the surface as quickly as possible, forming an active rust-proof protective layer. Therefore, its rust-preventing effect The adequate amount is shallow, and 0.喔%~0.05% of dodecenylsuccinic acid can be added to the turbine oil to obtain a satisfactory antirust outcome, and the amount in the antirust oil is about 1%. Dodecenylsuccinic acid has the property of not emulsification in water, and it is used in dehydration and antirust oils and oils that require anti-emulsification for instrument oil lamps. Dodecyl succinic acid has excellent rust resistance to black metal, copper, and aluminum. Because of its high acid value, the amount should not be too high. In the rust preventive oil, it is usually used in combination with dodecyl succinic acid and strontium petroleum sulfonate, hydrazine dinonylnaphthalene sulfonate, alkenyl imidazoline or the like.

 

6. Preparation of carboxylic acids and their metal soaps commonly used in rust preventive oils

Widely used in the production of rust preventive oil carboxylic acid and its metal soap corrosion inhibitor, there are automatic vegetable oils of linolenic acid, stearic acid, oleic acid, ricinoleic acid, palmitic acid, lauric acid, and its soap; There are naphthenic acids, oxidized petroleum esters, and oxidized ceresin; there are synthetic fatty acids such as alkenyl succinic acid, nonyl phenoxy acetic acid, and carboxylic fatty acids. The carboxylic acid type oil-soluble corrosion inhibitor has good anti-emulsification ability and is suitable for formulating oils requiring high demulsibility of the turbine oil lamp. The most used in the storage of antirust oil and dehydration antirust oil is dilute succinic acid, and more sulfonate corrosion inhibitors are used together. The rust inhibitor of the acid soap corrosion inhibitor is stronger than the corresponding acid, but the solubility in the oil is small. Carboxylic acid and dicarboxylic acid soaps are too polar to be soluble in fats. The acid soap corrosion inhibitor is often used to prepare and store antirust oil.