JPH07118685A - Anti-corrosive oil composition for bearing - Google Patents

Abstract

PURPOSE:To obtain the oil composition having excellent lubricating properties, load resistance, torque stability and corrosion prevention by mixing a base oil comprising a light refined mineral oil having specific kinetic viscosity and a refined mineral oil with neutral Ba sulfonate and a sorbitan fatty acid partial ester. CONSTITUTION:100 pts.wt. of a light refined mineral oil (e.g. parafinic light refined mineral oil) having 4-10mm<2>/s kinetic viscosity at 40 deg.C is mixed with 20-40 pts.wt. of a refined oil (e.g. paraffinic refined mineral oil) having 18-40mm2/s kinetic viscosity at 40 deg.C give a mixed oil as a base oil. The mixed oil is blended, based on the total of a composition, with (A) 5-25wt.% of neutral barium sulfonate, (B) 1-15wt.% of a partial ester of sorbitan and a 10-22C fatty acid (e.g. sorbitan monoisostearate) and (C) 0.1-1.0wt.% of a phenolic antioxidant (e.g. 2,6-di-t-butyl-p-cresol) to give the composition having 10-20mm<2>/s kinetic viscosity at 40 deg.C, excellent lubricating properties, load resistance, torque stability and corrosion prevention.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rust preventive composition for a bearing, and more particularly to a rust preventive oil composition which is particularly preferably used for a tapered roller bearing used for a pinion bearing of a differential gear device.

[0002]

BACKGROUND OF THE INVENTION Tapered roller bearings are used in a pre-loaded state in the axial direction in order to exert their functions effectively, but the pre-load cannot be measured after assembly. Therefore, the preload control is indirectly performed by measuring the torque from the outside. Therefore, the rust preventive oil applied to the tapered roller bearing at the time of shipment is required to have a function as an initial lubricant in order to enable preload control of the bearing in addition to the rust preventive function.

Further, especially when the friction torque is very small as in a pinion bearing of a differential gear device,
In order to obtain a constant preload by measuring the torque, the rust preventive oil having the function as the initial lubricating oil has excellent torque stability, and the viscosity changes greatly depending on the rotation speed,
It is required that it does not change over time. As the rust preventive oil currently used in the tapered roller bearing, a solvent diluted rust preventive oil (NP specified in JIS K2246) is used.
3-1) and lubricating oil type rust preventive oil (also NP-1
There is 0-1).

The former solvent-diluted rust preventive oil is a solution of petrolatum dissolved in a suitable solvent, and forms a thin light coating (a film of petrolatum) on the metal surface to protect the metal surface, so that it is rust preventive. Is excellent. However, since this solvent-diluted rust preventive oil forms a light coating by evaporation of the solvent, the viscosity changes momentarily after application due to evaporation of the solvent, and the formed light coating has a thick film thickness.
There is a problem in terms of torque stability such that the viscosity changes greatly depending on the rotational speed of the tapered roller bearing.

Moreover, since petrolatum is an adhesive substance, it sticks or sticks to the product or coating device, etc., to improve the workability of coating the bearing at the time of manufacturing the bearing and assembling the bearing to the differential gear device. In addition to the deterioration, the solvent that evaporates from the rust preventive oil and the petrolatum itself that sticks to the coating device may impair the working environment, which may impair the health of the worker.

On the other hand, the generally used lubricating oil type rust preventive oil is excellent in lubricity, load resistance, and torque stability because the rust preventive additive is added to the lubricant oil. Although it can be used as an initial lubricating oil at the time of measurement, it does not have the rust-preventing effect as that of the solvent-diluted type, and its rust-preventing property is insufficient. The present invention has been made in view of the above circumstances, and is a lubricating oil type excellent in lubricity, load resistance, and torque stability without using a petrolatum that may adversely affect workability and working environment. To provide an excellent rust preventive oil composition for a bearing, which can be used as it is as an initial lubricating oil at the time of torque measurement and has a rust preventive property similar to that of a solvent diluted type, especially for a tapered roller bearing by adopting the above constitution. It is an object.

[0007]

Means and Actions for Solving the Problems In order to solve the above problems, the present inventors conducted various studies on the type and viscosity of the base oil, the additive to be added and the amount added, and as a result, the rust was found. The present invention has been completed by finding the optimum combination and the optimum numerical range with excellent stopping property.

That is, the rust preventive oil composition for bearings according to claim 1 of the present invention has a kinematic viscosity at 40 ° C. with respect to 100 parts by weight of light refined mineral oil having a kinematic viscosity at 40 ° C. of 4 to 10 mm ² / s. Is 18 to 40 mm ² / s, and a mixed oil containing 20 to 40 parts by weight of refined mineral oil is used as a base oil.
(1) 5 to 25% by weight of neutral barium sulfonate, and (2) 1 to 15% by weight of a partial ester of sorbitan and a fatty acid having 10 to 22 carbon atoms, and a kinematic viscosity at 40 ° C. It is characterized in that it is in the range of 10 to 20 mm ² / s.

The rust preventive oil composition for bearings according to claim 2 of the present invention has a kinematic viscosity at 40 ° C. with respect to 100 parts by weight of light refined mineral oil having a kinematic viscosity at 40 ° C. of 4 to 10 mm ² / s. Is 1
A mixed oil containing 20 to 40 parts by weight of refined mineral oil of 8 to 40 mm ² / s was used as a base oil, and based on the total amount of the composition, (1) 5 to 25% by weight of neutral barium sulfonate, (2) ) 1 part of partial ester of sorbitan and fatty acid having 10 to 22 carbon atoms
To 15% by weight and (3) 0.1 to 1.0% by weight of a phenolic antioxidant, and a kinematic viscosity at 40 ° C. of 10 to 20 mm ² / s. And

The rust preventive oil composition for bearings of the present invention having the above-mentioned constitution has a lubricating property, a load bearing property and a torque stability which can be directly used as an initial lubricating oil at the time of torque measurement due to the synergistic effect of the above respective components. It has the same anti-rust property as the solvent diluted type. Also, since petrolatum is not used, there is no risk of adversely affecting workability or work environment.

The contents of the present invention will be described in more detail below. In the rust preventive oil composition for bearings of the present invention, the light refined mineral oil constituting the base oil is 4 to 10 mm ² / s at 40 ° C.
Preferably, it has a kinematic viscosity of 6 to 8 mm ² / s. When the kinematic viscosity of the light refined mineral oil is less than 4 mm ² / s, the torque stability is poor due to the change of the oil film strength due to the evaporation of volatile components in the light mineral oil, while when it exceeds 10 mm ² / s, the oil film is The decrease in the drying property of oil reduces the strength of the oil film, resulting in poor lubricity and rust resistance.

In the rust preventive oil composition for bearings of the present invention, the refined mineral oil which is another component of the base oil is 4
18-40 mm ² / s at 0 ° C, preferably 21-30 mm ²
It has a kinematic viscosity of / s. When the kinematic viscosity of the refined mineral oil is less than 18 mm ² / s, the lubricity and rust preventive property deteriorate due to the decrease of the oil film strength, while when it exceeds 40 mm ² / s, the final composition of the target composition is In order to obtain the viscosity, the blending ratio of the light mineral oil increases, and the torque stability deteriorates due to the change in the oil film strength due to the evaporation of the volatile components in the light mineral oil.

These light refined mineral oils and refined mineral oils are not particularly limited except for the above-mentioned kinematic viscosity range, and any one can be used as long as they are used as ordinary refined mineral oils. . Specifically, for example, a lubricating oil fraction obtained by distilling crude oil under atmospheric pressure and vacuum distillation is used for solvent degassing, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid washing. It is possible to use paraffin-based or naphthene-based mineral oil refined by appropriately combining refining treatments such as clay treatment.

In the present invention, the blending ratio of the light refined mineral oil and the refined mineral oil is 20 to 40 parts by weight, preferably 25 to 30 parts by weight, based on 100 parts by weight of the light mineral oil. When the blending amount of the refined mineral oil is less than 20 parts by weight, the volatile components in the base oil increase in volatility, and the oil content that contributes to lubrication relatively decreases, so that the lubricity decreases. On the other hand, when the amount of refined mineral oil is more than 40 parts by weight, oil dripping occurs and the additive component flows out accordingly, so that the rust preventive property of the rust preventive oil decreases.

Among the essential additive components constituting the rust preventive oil composition for bearings of the present invention, the component (1) is neutral (normal salt) barium sulfonate. The barium sulfonate as used herein is a barium salt of an alkylaromatic sulfonic acid obtained by sulfonating an alkylaromatic compound having a molecular weight of about 100 to 1500, preferably 200 to 700. Specific examples of the sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid.

The petroleum sulfonic acid as referred to herein is generally one obtained by sulfonating an alkyl aromatic compound of a lubricating oil fraction of mineral oil, or a by-product during the production of white oil.
So-called mahogany acid or the like is used. Further, as the synthetic sulfonic acid, for example, a product obtained by sulfonation of an alkylbenzene having a linear or branched alkyl group, which is obtained as a by-product from an alkylbenzene production plant which is a raw material of a detergent or obtained by condensing a polyolefin with benzene. Alternatively, sulfonation of alkylnaphthalene such as dinonylnaphthalene is used. The sulfonating agent used for sulfonating these alkyl aromatic compounds is not particularly limited, and fuming sulfuric acid or sulfuric anhydride is usually used.

The neutral barium sulfonate of the component (1) is obtained by reacting the above alkylaromatic sulfonic acid directly with a barium base such as an oxide or hydroxide of barium, or once as a sodium salt. To be replaced by a barium salt. The content of the neutral barium sulfonate of the component (1) in the present invention is 5 to 25% by weight, preferably 11% by weight based on the total amount of the composition.
~ 15% by weight. Ingredient (1) If the content is less than 5% by weight, the rust preventive performance is poor, while if the content exceeds 25% by weight, the effect is saturated and the content is justified. The effect of improving rust resistance cannot be obtained.

Among the essential additive components constituting the rust preventive oil composition for bearings of the present invention, the component (2) is composed of sorbitan and a fatty acid having 10 to 22 carbon atoms, preferably 12 to 18 carbon atoms. It is a partial ester. The partial ester as used herein means an ester in which at least one hydroxyl group in sorbitan remains in the form of a non-esterified hydroxyl group.

The fatty acid may be saturated fatty acid or unsaturated fatty acid, and may be linear fatty acid or branched fatty acid. Specifically, for example, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, heneicosanoic acid,
Saturated fatty acids such as docosanoic acid (all of them include all isomers); decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid,
Unsaturated fatty acids such as hexadecenoic acid, heptadecenoic acid, octadecenoic acid, nonadecenoic acid, eicosenoic acid, heneicosenoic acid, docosenoic acid (all of them include all isomers), and mixtures thereof can be mentioned.

Specific examples of the partial ester of the component (2) include, for example, sorbitan monododecanoate (sorbitan monolaurate), sorbitan monoisolaurate,
Sorbitan didodecanoate (sorbitan dilaurate), sorbitan diisolaurate, sorbitan tridodecanoate (sorbitan trilaurate), sorbitan triisolaurate, sorbitan monotetradecanoate (sorbitan monomyristate), sorbitan monoisomyristate , Sorbitan ditetradecanoate (sorbitan dimyristate), sorbitan diisomyristate, sorbitan tritetradecanoate (sorbitan trimyristate), sorbitan triisomyristate, sorbitan monohexadecanoate (sorbitan monopalmitate) ), Sorbitan monoisopalmitate, sorbitan dihexadecanoate (sorbitan dipalmitate), sorbitan diisopalmitate, sorbitan trihexadecanoe (Sorbitan tripalmitate), sorbitan triisopalmitate, sorbitan monooctadecanoate (sorbitan monostearate), sorbitan monoisostearate, sorbitan dioctadecanoate (sorbitan distearate), sorbitan diisostearate Sorbate, sorbitan trioctadecanoate (sorbitan tristearate), sorbitan triisostearate, sorbitan monooctadecenoate (sorbitan monooleate), sorbitan monoisooleate, sorbitan dioctadecenoate (sorbitan diole) Ate), sorbitan diisooleate, sorbitan trioctadecenoate (sorbitan trioleate), sorbitan triisooleate, and mixtures thereof. Sterbit sorbitan monododecanoate (sorbitan monolaurate), sorbitan monoisolaurate, sorbitan monotetradecanoate (sorbitan monomyristate), sorbitan monoisomyristate, sorbitan monohexadecanoate (sorbitan monopalmi) Tate), sorbitan monoisopalmitate, sorbitan monooctadecanoate (sorbitan monostearate), sorbitan monoisostearate, sorbitan monooctadecenoate (sorbitan monooleate),
Sorbitan monoisooleate and mixtures thereof are preferably used.

In the present invention, the content of the partial ester of the component (2) is 1 to 15% by weight, preferably 5 to 8% by weight based on the total amount of the composition. The content of component (2) is 1% by weight
If it is less than the range, the anticorrosive performance and the lubricity are poor, while if the content exceeds 15% by weight, the torque value is lowered. In the present invention, petrolatum which may adversely affect workability and work environment by combining the above-mentioned two types of base oils and two additives of components (1) and (2) as essential components in specific amounts It is possible to use it as an initial lubricating oil for torque measurement as it is, while using a lubricating oil type configuration that has excellent lubricity, load resistance, and torque stability without using It is possible to obtain a rust preventive oil composition for bearings, which is excellent especially for tapered roller bearings.However, in order to stabilize the lubricity and rust preventive property of the oil film during long-term storage, phenol (Component (3)) is further added. A system antioxidant can be used together.

Specific examples of the phenolic antioxidants mentioned here include 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol and 2
-Methyl-6-tert-butyl-p-cresol, 4,
4'-methylenebis (2,6-di-tert-butylphenol), 4,4'-bis (2,6-di-tert-butylphenol), 4,4'-thiobis (6-tert-butyl-)
o-cresol), and mixtures thereof.

In the present invention, when the phenolic antioxidant of the component (3) is used in combination, its content is 0.1 to 1.0% by weight, preferably 0.4 to 10% by weight based on the total amount of the composition.
It is 0.6% by weight. The content of component (3) is 0.1% by weight
When it is less than the above, the effect of addition, that is, the effect of stabilizing the lubricity and rust preventive property of the oil film during long-term storage is not sufficiently exerted, while even when the content exceeds 1.0% by weight,
The effect is only saturated, and the effect commensurate with the content cannot be obtained.

In the present invention, for the purpose of further improving its excellent performance, known additives used in ordinary rust preventive oils may be used in combination. Specific examples of these known additives include, for example, wetting agents such as diethylene glycol monoalkyl ether; metal deactivators such as benzotriazole and alkyl thiadiazole; film forming agents such as acrylic polymers and paraffin wax; water such as fatty acid amine salts. Displacement agents; zinc dialkyldithiophosphates, sulfurized fats and oils, extreme pressure agents such as phosphorus compounds, and the like,
These may be used alone or in combination of two or more. The content in the case of using these known additives in combination is arbitrary, but normally, the total content of these known additives is preferably about 0.1 to 10% by weight based on the total amount of the composition.

Furthermore, a low boiling point mineral oil-based solvent such as mineral spirit may be appropriately blended with the rust preventive oil composition for bearings of the present invention. In the rust preventive oil composition for bearings of the present invention, the composition has a kinematic viscosity of 1 at 40 ° C.
It should be in the range of 0 to ²⁰ mm ² / s, preferably 13 to 15 mm ² / s. When the kinematic viscosity is less than 10 mm ² / s, the lubricity decreases and the change of torque with time becomes large, while when the kinematic viscosity exceeds 20 mm ² / s, the film thickness of the rust preventive oil increases. In any case, there is a problem in terms of torque stability, because the viscosity tends to greatly change depending on the rotation speed of the bearing. On the other hand, the rust preventive oil composition for a bearing of the present invention, whose kinematic viscosity at 40 ° C. is adjusted within the range of 10 to 20 mm ² / s, exhibits good lubricity.
The rotational torque value of the bearing coated with this shows the optimum value,
In addition, the fluctuation of the torque value due to the change of the rotation speed is small. Also, changes in lubricity and torque value over time are prevented.

The rust preventive oil composition for bearings of the present invention is particularly preferably used for tapered roller bearings, but specifically, for example, cylindrical roller bearings and self-aligning rollers other than tapered roller bearings. Roller bearings such as bearings and needle roller bearings; deep groove ball bearings, maximum type ball bearings, angular contact ball bearings, four-point contact ball bearings, self-aligning ball bearings, plane thrust ball bearings, aligning thrust ball bearings, thrust Suitable for ball bearings such as angular contact ball bearings; and special purpose bearings such as bearings for railroad vehicle axles, rolling mill roll neck bearings, turntable bearings, textile machine bearings, cam followers and slide bearings. it can.

The rust preventive oil composition for bearings of the present invention can be applied to the bearing by a method such as a dipping method or a spraying method, as in the case of conventional lubricating oil type rust preventive oils. As described above, the rust preventive oil composition for bearings of the present invention has the synergistic effect of each of the above-mentioned components, and thus can be used as it is as an initial lubricating oil at the time of torque measurement, load resistance, torque stability, and solvent dilution type. It also has anti-rust properties. In addition, since petrolatum is not used, there is no risk of adversely affecting workability and work environment.

[0028]

EXAMPLES Hereinafter, the contents of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these contents. <Examples 1 to 4 and Comparative Examples 1 to 4> The composition shown in Table 1 was used to prepare a rust preventive oil composition for bearings (Examples 1 to 4 according to the present invention. According to the composition shown in Table 3, two kinds of base oils, which are essential components of the present invention,
Also, compositions (Comparative Examples 1 to 4) not containing any one of the components (1) to (3) were prepared. The components used are as follows.

Light refined mineral oil I: paraffinic light refined mineral oil (kinematic viscosity at 40 ° C. 6.5
mm ² / s) II: Lightly refined naphthene mineral oil (Kinematic viscosity at 40 ° C 6.5 mm
² / s) Refined mineral oil III: Paraffin refined mineral oil (kinematic viscosity at 40 ° C. 22.0
mm ² / s) IV: Natefun refined mineral oil (Kinematic viscosity at 40 ° C. 22.0 mm ²
/ S) Component (1): Neutral barium sulfonate V: Neutral barium dinonylnaphthalene sulfonate VI: Neutral barium alkylbenzene sulfonate Component (2): Partial ester of sorbitan VII: Sorbitan monoisostearate VIII: Sorbitan monooleate component (3): Phenolic antioxidant IX: 2,6-di-tert-butyl-p-cresol Test 1 Rust preventive oil compositions of Examples 1 to 4 and Comparative Examples 1 to 4 The following tests were carried out to evaluate the performance.
For comparison, the same test was performed on a solvent-diluted rust preventive oil (conventional product a = Comparative Example 5) and a lubricating oil rust preventive oil (conventional product b = Comparative Example 6) for comparison.

The above results were measured according to JIS K 2283, kinematic viscosity at 40 ° C. (mm ² / s), and measurement of the oil film thickness according to JIS K 2246 4.16. The results are also shown in Tables 1 to 3. [Salt Water Spray Test] The test time until rust was generated was measured based on the salt water spray test specified in JIS K 2246 5.35, and evaluated in the following three stages.

A: 48 hours or more B: 24 hours or more and less than 48 hours C: less than 24 hours [Wet test] The test time until rust was generated in accordance with the wet test defined in JIS K 2246 5.34. It was measured and evaluated in the following 5 stages.

A: 1000 hours or more B: 800 hours or more and less than 1000 hours C: 600 hours or more and less than 800 hours D: 400 hours or more and less than 600 hours E: Less than 400 hours [Dew test] JIS K 2246 5.36 According to the weather resistance test method specified in, but using a tester manufactured by Yamazaki Seiki Co., Ltd. as a device under the conditions of dew / dry cycle and UV irradiation, and measure the time when rust occurs to evaluate. did.

[Outdoor exposure test] JIS K 2246
According to the packaging and storage test method specified in 5.37, the period (month) when rust occurred was measured and evaluated.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

Test 2 The rust preventive oil composition of the present invention of Example 3 and the rust preventive oil of the conventional product a of Comparative Example 5 were each applied to a tapered roller bearing (inner diameter φ30 mm), and immediately after application. The transition of the rotational torque (N · m) was measured from the start to 3 months.
The results are shown in Fig. 1. The solid line in the figure indicates the change in the rotational torque of the tapered roller bearing of Example 3 coated with rust preventive oil (○)
-○ indicates a rotation speed of 60 rpm, and ◇-◇ indicates a rotation speed of 100 rpm.
m.), and the broken line indicates changes in the rotational torque of the tapered roller bearing of Comparative Example 5 coated with rust preventive oil (●-● indicates a rotational speed of 6).
0r.pm, ◆-◆ indicates the number of revolutions 100r.pm).

As can be seen from the figure, the tapered roller bearing coated with rust preventive oil of the conventional product a has a remarkably reduced rotational torque, while the tapered roller bearing coated with rust preventive oil of Example 3 has three rollers. The rotation torque did not change even after the lapse of months. It is conceivable that the solidification of the film due to the evaporation of the solvent is one of the causes of the decrease in the rotational torque of the tapered roller bearing of the conventional product a coated with rust preventive oil with the passage of time. That is, the rust preventive oil of the conventional product a has a petrolatum content of 30% at the time of application due to evaporation of the solvent, as can be seen from FIG.
After 20 hours, it reaches 80% (the solvent is evaporated by that amount). Also, apply 1 at 25 ℃
The viscosity was 2 mm ² / s but after 4 hours it was 14 at 25 ° C.
It has also been confirmed that it can rise to 8 mm ² / s.

Test 3 The rust preventive oil composition of the present invention of Example 3 and the rust preventive oil of the conventional product a of Comparative Example 5 were applied to the same tapered roller bearing as in Test 2 to adjust the rotation speed. The change in the rotational torque (N · m) when changing was measured. The results are shown in Fig. 3. In the figure, the solid line shows the change in the rotational torque of the tapered roller bearing of Example 3 coated with rust preventive oil, and the broken line shows the change of the rotational torque of the tapered roller bearing coated with rust preventive oil of Comparative Example 5. There is.

As can be seen from the figure, in the tapered roller bearing of the conventional product a coated with rust preventive oil, the rotational torque greatly changed with the change in the number of revolutions, but the rust preventive oil of Example 3 was applied. The tapered roller bearing had a substantially constant rotational torque. Test 4 The rust preventive oil composition according to the present invention of Example 3 and the rust preventive oil of the conventional product a of Comparative Example 5 were applied to the same tapered roller bearing as in Test 2 and rotated while applying a predetermined load. The time during which the bearing seized (seizure life, seconds) was measured to determine the relationship between the load (kN) and the seizure life. The results are shown in Fig. 4. In the figure, the solid line shows the relationship between the load and the seizure life of the tapered roller bearing coated with rust preventive oil of Example 3, and the broken line shows the load and the seizure life of the conventional tapered roller bearing coated with rust preventive oil a. Shows the relationship with.

As shown in the figure, the tapered roller bearing coated with rust preventive oil of Example 3 has a load of less than 1500 kN as compared with the conventional tapered roller bearing coated with rust preventive oil a. It was found that the baking life was significantly improved. From the results of the above-mentioned tests 2 to 4, it was confirmed that the rust preventive oil compositions of Examples had much better lubricity, load resistance, and torque stability than the conventional solvent-diluted product a. .

[0042]

As described above in detail, the rust preventive oil composition for bearings of the present invention can be used as it is as an initial lubricating oil at the time of torque measurement due to the synergistic effect of each component constituting the rust preventive oil. It has both lubricity, load bearing capacity, torque stability, and rust preventive properties similar to those of a solvent dilution type. Also, since petrolatum is not used, there is no risk of adversely affecting workability or work environment.

[Brief description of drawings]

FIG. 1 is a diagram showing a rust preventive oil according to a third embodiment of the present invention and a conventional solvent-diluted product applied to a tapered roller bearing, respectively.
It is a graph which shows a time change of rotation torque.

FIG. 2 is a graph showing changes in concentration of the conventional solvent-diluted product.

FIG. 3 is a graph showing the relationship between rotational torque and rotational speed when the rust preventive oil of Example 3 and the conventional solvent-diluted product were applied to tapered roller bearings.

FIG. 4 shows the load and seizure life when the rust preventive oil of Example 3 and a conventional solvent-diluted product are applied to a tapered roller bearing and rotated while applying a predetermined load to the bearing. It is a graph which shows the relationship of.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location C10M 135: 10 129: 76 129: 10) C10N 20:02 30:12 40:02 (72) Invention Komiya Hiroshi 3-5-8 Minamisenba, Chuo-ku, Osaka City Koyo Seiko Co., Ltd. (72) Inventor Yukio Matsuzaki 8 Chidori-cho, Naka-ku, Yokohama City Central Research Institute of Japan Petroleum Stock Company (72) Inventor Mitsuo Koike Yokohama 8 Chidori-cho, Naka-ku, Japan Inside the Central Research Institute of Japan Oil Co., Ltd.

Claims (2)

[Claims] 1. A relative light refined mineral 100 parts by weight of kinematic viscosity 4 to 10 mm ² / s at 40 ° C., a kinematic viscosity at 40 ℃ 18~40mm ² / s of the purified mineral oil 20 to 40 parts by weight (1) 5 to 25% by weight of neutral barium sulfonate, and (2) partial ester of sorbitan and a fatty acid having 10 to 22 carbon atoms, based on the total amount of the composition. 1 to 15% by weight, and the kinematic viscosity at 40 ° C. is within the range of 10 to 20 mm ² / s. 2. A relative light refined mineral 100 parts by weight of kinematic viscosity 4 to 10 mm ² / s at 40 ° C., a kinematic viscosity at 40 ℃ 18~40mm ² / s of the purified mineral oil 20 to 40 parts by weight The base oil is a mixed oil containing (1) 5 to 25% by weight of neutral barium sulfonate and (2) partial ester of sorbitan and a fatty acid having 10 to 22 carbon atoms. 1 to 15% by weight, and (3) 0.1 to 1.0% by weight of a phenolic antioxidant,
A rust preventive oil composition for bearings, which contains and has a kinematic viscosity at 40 ° C. in the range of 10 to 20 mm ² / s.