JPS6018590A - Inhibitor for metal corrosion - Google Patents

Abstract

PURPOSE:An inhibitor for metal corrosion, useful for a heat-resistant lubricating oil, comprising a benzotriazole or a 2,5-dialkyldithio.thiadiazole and a specific organotin compound as active ingredients. CONSTITUTION:The desired inhibitor for metal corrosion comprising (A) a benzotriazole and/or 3-18C 2,5-dialkyldithio.thiadiazole, and (B) organotin compound(e.g., di-butyltin-di-laurate, etc.) shown by the formula(R and R' are 1- 18C alkyl; R'' and R''' are 3-22C carboxyl, maleate, or 3-18C maleate monoester, 1-18C mercapto, 3-18C mercaptoacetic ester, or 1-18C alkoxy) as active ingredients. A blending ratio of the component A to B is preferably 100:(10- 1,000) by weight.

Description

[Detailed description of the invention] The present invention relates to metal corrosion inhibitors for lubricating oils.

More specifically, 1111 or 2 or more of benzotriazoles or 2,5-diazokyldithiothiadiazoles having 4 to 18 carbon atoms, - represents an alkyl group having 1 to 18, and R/ and R'' are Carbon number is 3 to 2
2 carboxyl groups, maleate groups, carbon number 3 to 1
8 maleate monoester group, a mercapto group having 1 to 1 carbon atoms, a mercaptoacetate group having 3 to 18 carbon atoms, and an alkoxy group having 1 to 18 carbon atoms.

The present invention relates to a heat-resistant metal corrosion inhibitor comprising, as an active ingredient, one or more organic tin compounds represented by the following formulas.

Conventionally, motor oil, gear oil and 1 hydraulic oil.

Antioxidants, pour point depressants, etc. are used to improve oil properties and enable long-term use.

Appropriate amounts of additives such as viscosity index improvers, detergent dispersants, extreme pressure agents, and rust inhibitors are added. Many of these additives are inert to metals, but they are effective to compounds such as extreme pressure agents and antioxidants.

Contains substances that corrode metals.

To prevent this, fatty acids and amines.

Amides, sulfonic acids, etc. were added. Although these anticorrosive agents effectively protect metals from corrosion at temperatures below 12 otE, their anticorrosion effect decreases at humidity higher than that.

Recently, the conditions for using lubricating oil have become harsher, with temperatures ranging from 150 to 300℃.
There is a need to suppress corrosion of metals even at higher temperatures, and the development of heat-resistant metal corrosion inhibitors has been desired.

The present inventor has finally completed the present invention as a result of various studies on anticorrosive agents with excellent heat resistance.

That is, it has been found that di-alkyl tin compounds have good Jb solubility and are very stable against heat, and when used in combination with triazoles and thiadeazoles, metals, especially copper.

It was discovered that it has excellent corrosion resistance against copper alloys, iron, aluminum, etc.

Among lubricating oil additives such as extreme pressure agents and antioxidants.

Examples of substances that corrode metals at high temperatures include dithiophosphates and dithiocarbamates.

These compounds are relatively stable at temperatures of 100-120°C, but at higher temperatures they gradually thermally decompose and release sulfur.

This liberated sulfur reacts with metal to form metal sulfide, causing corrosion.

It is believed that the metal corrosion inhibitor of the present invention not only prevents the formation of metal sulfides caused by dithiophosphates and dithiocarbamates, but also has the effect of preventing thermal decomposition of these compounds. The resulting oil has little discoloration and no sludge is formed.

Benzotriazoles and thiadiazoles.

It has traditionally been used as a rust preventive agent for copper layers.

These alone have an excellent anti-corrosion effect only at temperatures up to about 120°C, and at temperatures higher than this.

The formation of metal sulfides cannot be prevented.

Benzotriazoles or thiadiazoles and di-
Only by cooperating with an alkyl-tin compound can the corrosion of metals at high temperatures of 150 to 300° C., which is the object of the present invention, be prevented.

The dialkyl tin compound according to the present invention is.

It is itself a non-J-stable compound against heat.

It has the effect of stabilizing polymer compounds and the like. Therefore, in the present invention, thermal decomposition and oxidative deterioration of dithiophosphates and dithiocarbamates are suppressed,
Preventing the release of sulfur, which is a corrosion factor, can be considered to be one factor in preventing corrosion of metals including copper.

It is also believed that it prevents the decomposition of the metal protective chelate film formed on the metal surface and maintains its anticorrosion effect for a long period of time.

The combined ratio of these two compound groups is 100% of benzotriazoles or di-alkyldithiothiadiazoles.
The dialkyl tin compound is preferably in the range of 1 to 2000 parts by weight based on parts by weight of the di-alkyl tin compound;
The tin compound is 10 to 1000 parts by weight.

Combinations other than the cholera ratio cannot completely prevent corrosion of metals caused by dithiophosphates and dithiocarbamates.

The benzotriazoles according to the present invention.

Benzotriazole, methylbenzotriazole, chlorbenzotriazole, carboxybenzotriazole, ethylbenzotriazole.

Examples of di-alkyldithio thiadiazoles include naphthotriazole, etc.
Examples include butyldithio thiadiazole, di-t-hexyldithio thiadiazole, di-octyldithio thiadiazole, di-lauryldithio thiadiazole, dioleyldithio thiadiazole, and the like.

Examples of di-alkyl tin compounds according to the present invention include di-ethyl tin di-stearate, dibutyl Φ tin dilaurate, and di-octyl tin di-stearate.
G-stearate.

Di-lauryl tin-di-laurate, di-butyl tin-octyl maleate-butoxide, di-butyl tin-octyl maleate-butoxide, di-butyl tin-tin di-nonyl maleate, di-butyl tin-octyl maleate, bis-(di- butyl tin monooleate) maleate, bis(dibutyl tin octyl maleate) maleate, dibutyl tin monooleate) maleate, dibutyl tin monooleate) maleate, dibutyl tin monooleate) maleate, dibutyl tin octyl maleate
Examples include oleyl sulfide, di-butyl-tin-8-8'-bis-(octylmercaptoacetate), di-octyltin-5-s'-his-(dodecylmercaptoacetate), and the like.

The metal corrosive agent according to the present invention includes fatty acid salts and amines, which are conventionally used anticorrosive agents.

It can be used in combination with amides or sulfonic acids for a more complete effect.

Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

Example 1 0.8 parts by weight of zinc-di-octyl-dithiophosphate and 0.2 parts by weight of molybdenum-di-butyl-dithiocarbamate were uniformly dissolved in 99 parts by weight of 1F30 engine oil, and further After each of the products of the present invention shown in Table 1 was added and uniformly dissolved.

Degreased copper, phosphor bronze, and steel specimens were immersed in
Heated at 30±5°C for 10 hours. After heating, the test piece was taken out, immersed in 10N hydrochloric acid for 10 minutes to remove corrosive substances, washed with water, dried, and weighed to measure the change in weight.

Table 1 As is clear from the above results, the product of the present invention was found to have an excellent anticorrosion effect on metals.

Example 2 98.5 parts of e30 gear oil, 0.7 part of sulfurized whale oil, 0.5 part of 8 zinc-di-octyl dithiophosphate, and 1 part of moly.
Test pieces of brass, Namari bronze, and aluminum that were uniformly dissolved with 0.3 part of Denzyoctyl dithiophosphate, each of the products of the present invention shown in Table 2 were added, uniformly dissolved, and then degreased. was immersed and heated at 200±5°C for 7 hours. After heating, the test piece was immersed in 10N hydrochloric acid for a portion to remove corrosive substances, washed with water, dried, and the change in weight was measured.

Table 2 As is clear from the above results, the product of the present invention was found to have an excellent anticorrosion effect on metals.

that's all patent applicant Chiyoda Chemical Research Institute Co., Ltd. −to

Claims (1)

[Claims] Benzotriazoles or 2 having 4 to 18 carbon atoms
．． 5-di-alkyldithiothiadiazole (in the formula, R
and R' represents an alkyl group having 1 to 18 carbon atoms, and 1
w' and r are a carboxy group having 3 to 22 carbon atoms, a ru group, a maleate group, a maleate monoester group having 3 to 18 carbon atoms, a mercapto group having 1 to 18 carbon atoms, a mercapto group having 3 to 18 carbon atoms; It represents a mercaptoacetate group and an alkoxy group having 1 to 18 carbon atoms. ) A metal corrosion inhibitor for lubricating oil comprising as an active ingredient one or two of the organic tin compounds represented by the following.