Lubricative Composition for Industrial Machinery and Equipment

Abstract

A lubricative composition for industrial machinery and equipment which comprises a base oil selected from among mineral oils, fats and oils, synthetic oils and mixture of two or more of them, and at least one additive selected from among the following components (A) to (D): component (A): (A-1) a phosphorus-containing carboxylic acid and / or (A-2) a thiophosphoric ester, component (B): a dispersant viscosity index improver, component (C): (C-1) a specific amidocarboxylic acid compound and / or (C-2) a specific carboxylic acid compound, and component (D): an ester oiliness improver. The composition is favorable as a lubricating oil composition and useful as a gear oil composition, a lubricating oil composition for paper machines or a lubricating oil composition for slide guides, a hydraulic oil, or the like.

Description

TECHNICAL FIELD[0001]The present invention relates to a novel lubricative composition for industrial machinery and equipment, more specifically, to a lubricating oil composition with excellent lubricative characteristics such as the abrasion resistance, the extreme pressure property, the frictional property and the like, as well as excellent in characteristics required according to the use of industrial machinery and equipment, and even more specifically, to a gear oil composition, a lubricating oil composition for paper machines, a lubricating oil composition for slide guides and a hydraulic oil. In particular, the gear oil composition is excellent in the sludge resistance and the extreme pressure property, the lubricating oil composition for paper machines is excellent in the sludge resistance and the extreme pressure property, the lubricating oil composition for slide guides is excellent in both aspects of the frictional property and the anti-stick-slip property, and the hydrauli...

AI Technical Summary

Benefits of technology

[0030]The gear oil composition is excellent in the sludge resistance and the extreme pressure property.

[0032]The lubricating oil composition for paper machines is excellent in the sludge resistance and the extreme pressure property.

[0034]The lubricating oil composition for slide guides is excellent in both aspects of the frictional property and the anti-stick-slip property.

[0043]The hydraulic oil is excellent in all the sludge suppression property, the abrasion resistance and the frictional property.

Problems solved by technology

However, the conventional gear oil, when used in the gear of the recent industrial machines, was not always sufficient in the sludge resistance and the extreme pressure property.

That is, for the use required to have high extreme pressure property and abrasion resistance, a lubricating oil added with the extreme pressure agent such as zinc dialkyldithiophosphate is widely used, but even if these conventional extreme pressure agents are added in small amount, thermal load is increased and a great amount of sludge is generated, and there is tendency to lower thermal and oxidation stability.

Therefore, it is difficult for the lubricating oil added with the sulfur-based extreme pressure agent to reach sufficient thermal and oxidation stability in the gear of the recent industrial machines.

Meanwhile, the phosphorus-based extreme pressure agent has tendency not to generate sludge easily compared with the sulfur-based extreme pressure agent, but when the phosphorus-based extreme pressure agent is used alone, it is difficult to obtain high extreme pressure property in the gear oil level.

Moreover, after making a paper in the paper machine, there is a step of drying the paper, but in the conventional paper machine, the drying time is comparatively long and the drying temperature is also comparatively low.

However, in the recent paper machines, the drying time became short in the drying step to improve the production efficiency, as a result, the drying temperature also became very high, and demand for the heat resistance in the lubricating oil used in the paper machine has increased.

Here, in order for the conventional lubricating oil for paper machines to improve abrasion resistance, using the extreme pressure agent is general, but if the extreme pressure agent is used, the heat resistance is deteriorated, and sludge, cocking or the like is easily generated in the lubricating portion.

In order to inhibit sludge, using a great amount of metal-based refining agent or ashless dispersant has been considered, but if these are used, the anticorrosion property is lowered, and problems such as the main body of the paper machine being corroded and the like are generated.

As a result, it is difficult to satisfy all the required performances such as the heat resistance, abrasion resistance and anticorrosion property.

For example, the lubricating oil for paper machines with excellent heat resistance, abrasion resistance and anticorrosion property is suggested in the Patent Document 3 (JP-A No. 2002-97485), but it does not always satisfy the performances.

Further, when stick-slip is generated on the slide guide such as a process table of machine tool, its frictional vibration is transferred to the product as is; as a result, problems such as the processing accuracy being decreased and the tool life being reduced from the vibration are generated.

However, having both the frictional property and anti-stick-slip property is not always easy, and the conventional lubricating oil composition for slide guides did not have sufficiently satisfying performances.

Meanwhile, due to the revision of the energy-saving laws, to the factories appointed as the energy supervision appointed factories, energy-saving has become an essential problem.

For example, as the abrasion resistant of the hydraulic oil, a zinc-based abrasion resistant such as zinc dithiophosphate (ZnDTP) is widely used, but the zinc-based abrasion resistant can cause sludge generation.

Further, the abrasion resisting effect by using ZnDTP or the like may form rigid film such as iron phosphate on the surface of the metal, and by such film formation, the frictional index of the sliding part is increased, thus it is said to be not preferable in the viewpoint of energy-saving.

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