JP2805207B2 - Hydraulic oil composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a hydraulic oil, particularly a rust-proof property of hydraulic oil for construction machinery,
The present invention relates to a method for improving demulsification properties and preventing the generation of sludge.

[Conventional technology]

Hydraulic oil for construction machinery has severe usage conditions, -20 ℃
Used under severe conditions of ~ 120 ° C. Therefore, the hydraulic oil is subject to heat and oxidative deterioration during use, causing the generation of sludge and causing troubles such as filter clogging. In addition, the hydraulic device is used under a natural environment, so that water is mixed therein, and the demulsifying property is strictly required.

[Problems to be solved by the invention]

In the conventional hydraulic oil composition, alkenyl succinic acid or a partial ester thereof as a rust preventive, and a neutral alkaline earth metal sulfonate-based one is used,
When used in a hydraulic device under severe operating conditions, there is a problem in that the filter is affected by heat or oxidative deterioration to generate sludge and clog the filter. Further, when a detergent dispersant is added to suppress the generation of sludge, a new problem of a decrease in demulsifying properties occurs.

[Means for solving the problem]

In order to improve the rust resistance and demulsification properties of such a hydraulic oil composition and to prevent the generation of sludge, the method of the present invention provides a lubricating base oil having an ISO viscosity grade of 10 to 460 with TB oil.
An alkaline earth metal sulfonate-based rust inhibitor having an N value of 40 to 100 is used in an amount of 0.01% by weight to 2.0% by weight based on the total amount of the hydraulic oil composition.
It is characterized by being added.

The alkyl earth metal sulfonate-based rust inhibitor used in the method of the present invention is usually the most commonly used as a rust inhibitor, and the sulfonic acid is a sulfone of an aromatic hydrocarbon component in a lubricating oil fraction. Of petroleum sulfonic acid, dinonylnaphthalenesulfonic acid (GB Patent 812,131, German Patent 1074794) and heavy alkylbenzene sulfonic acid (US Pat. No. 2,450,585) obtained by Such a synthetic sulfonic acid is used, and is prepared by converting it into an alkaline earth metal salt. For example, the following can be used.

Product name NA-SUL CA-50 Made by RTVANDERBILT NA-SUL CA-100 〃 NA-SUL 611 〃 BASIC BARIUM PETRONATE WITCO BRYTON HYBASE BARIUM 〃 BASIC CALCIUM PETRONATE 〃 LUBRIZOL 236 LOBRIZOL Also this alkaline earth metal sulfonate rust preventive TB
The N value must be between 40 and 100. TBN value means Total Base Number and is defined by JIS K2501 as the mg number of hydrochloric acid or perchloric acid and equivalent potassium hydroxide required to neutralize all basic components contained in 1 g of sample. Things.

This alkaline earth metal sulfonate-based rust inhibitor having a TBN value of 40 or less cannot neutralize acidic products generated by heat and oxidative deterioration, leading to sludge generation, and a TBN value of 100 or more. Although it is excellent in suppressing the generation of sludge, it loses the demulsifying properties required for hydraulic oil, and also loses the function as a rust inhibitor, and the TBN of the alkaline earth metal sulfonate rust inhibitor of the present invention The value range is extremely important.

The addition amount of such an alkaline earth metal sulfonate-based rust inhibitor is preferably 0.01% by weight to 2.0% by weight, and more preferably 0.1% by weight to 0.5% by weight, based on the total amount of the hydraulic oil.
If the added amount is out of this range, the desired effect cannot be obtained.

The base oil to which the alkaline earth metal sulfonate-based rust inhibitor is added is ISO viscosity grade 10-460 (9-506 cSt, 40
° C), preferably 22 to 68 (19.8 to 74.8 cSt, 40 ° C). Use a petroleum fraction or a refined product thereof as a mineral oil, or diester oil, polyolefin oil, etc. as a synthetic oil. Can be. If the viscosity of the base oil is less than this range, the pump used in the hydraulic device may seize, which is not preferable, and if it exceeds this range, the pour point becomes high, and if the environmental temperature is low, Is not preferred.

To the hydraulic oil composition according to the method of the present invention, in addition to an alkaline earth metal sulfonate-based rust inhibitor, an antiwear agent, an antioxidant, a metal deactivator, a pour point depressant, and an antifoaming agent are added. be able to. These additives can be used in an amount of 30% by weight or less based on the total amount of the composition.

Examples of the wear inhibitor include zinc thiophosphate-based wear inhibitors such as zinc primary alkylthiophosphate, zinc secondary alkylthiophosphate, zinc primary / secondary alkylthiophosphate, and zinc allylthiophosphate. It is preferable to use 0.1% by weight to 1.0% by weight based on the total amount of the hydraulic oil.

As antioxidants, commonly used antioxidants can be used. For example, 2.6-di-t-butylparacresol, 4.4'-methylenebis (2.6-di-t-butylphenol), 4.4'-thiobis ( 2-methyl-6-t
-Butylphenol) and 4.4'bis (2.6-di-t-
Phenol-based antioxidants such as butylphenol); amine-based antioxidants such as phenyl-α-naphthylamine and bis (alkylphenyl) amine;
Disulfide, zinc dithiocarbamate, and the like can be used, and the preferable addition amount is 0.1% by weight to 2.5% by weight based on the total amount of the hydraulic oil.

As the pour point depressant, polyalkyl methacrylate, polyalkyl acrylate, polyisobutylene, and the like can be used.
~ 20% by weight.

As an antifoaming agent, silicone, polyalkyl acrylate, and the like can be used, and the amount of use is 1 to the total amount of hydraulic oil.
~ 1000 ppm.

[Action]

The hydraulic oil composition according to the method of the present invention neutralizes acidic products generated by heat and oxidative deterioration by using those having TBN values of 40 to 100 as alkaline earth metal sulfonate-based rust inhibitors. It is stable against heat and oxidizing action, and can be made sludge-free. At the same time, it has the demulsifying properties required for hydraulic oils and also functions as a rust inhibitor. It can be held.

 Hereinafter, the present invention will be described with reference to examples.

[Examples / Comparative Examples]

Using 100 parts by weight of mineral oil having ISO viscosity grade VG46 as a base oil, 0.5 parts by weight of zinc thiophosphate as an antiwear agent, 0.2 parts by weight of 2.6-di-t-butylparacresol as an antioxidant, and pour point 0.2 polyalkyl methacrylate as depressant
Parts by weight ・ 0.0005 parts by weight of silicone as defoaming agent ・ barium sulfonate having a TBN value of 50 as a rust inhibitor, C
a-sulfonate TBN value 0, Ca-sulfonate TBN
The value of 50, the value of Ca-sulfonate TBN value of 200 (in this case, it has no rust-preventive function, but is shown for comparison), succinimide and succinate are shown in the table below. Examples 1 to
3. The hydraulic oil compositions of Comparative Examples 1 to 4 were prepared.

These hydraulic oil compositions, lubricating oil oxidation stability test method specified in JIS K2514, namely, immersing steel and copper catalyst in the sample, oxidized at 140 ° C. for 240 hours, observed the state of generation of sludge .

In addition, regarding the demulsifying property, the lubricating oil demulsifying property test method specified in JIS K2520, that is, 40 ml of a sample and 40 ml of water are placed in a sample container, kept at 54 ± 1 ° C., and stirred at 1500 ± 15 rpm for 5 minutes, The time for the resulting emulsion to separate into water and oil was measured.

The compositions of the hydraulic oil compositions of Examples 1 to 3 and Comparative Examples 1 to 4 and the test results are shown below.

[Effect of the Invention] The hydraulic oil composition according to the method of the present invention shows stability against heat and oxidative deterioration and does not generate sludge, and at the same time, has the demulsifying properties and protection required for hydraulic oil. It has excellent rust properties.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10N 30:12 40:08 (72) Inventor Shozo Matsushita 1-3-1 Nishitsurugaoka, Oimachi, Iruma-gun, Saitama Prefecture Toa Fuel Industries Co., Ltd. (72) Inventor: Saburo Tsunoda 1-3-1, Nishitsurugaoka, Oi-machi, Iruma-gun, Saitama Prefecture Toa Fuel Industry Co., Ltd. (56) References JP-A-55-73790 (JP, A JP-A-50-159432 (JP, A) JP-A-50-34003 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C10M 135/10 C10N 10:04 C10N 40: 08 C10N 20:02 C10N 30:12 C10N 30:00

Claims (1)

(57) [Claims] (1) To a lubricating base oil having an ISO viscosity grade of 10 to 460, an alkaline earth metal sulfonate rust inhibitor having a TBN value of 40 to 100 is added in an amount of 0.01 to 2.0% by weight based on the total amount of the composition. A method for improving the rust resistance and demulsification properties of a hydraulic oil composition and preventing the generation of sludge thereof.