JP2022123601A - lubricating grease composition - Google Patents

Abstract

To provide a lubricating grease composition that has high static frictional force and excellent wear resistance in sliding between metal members.SOLUTION: A lubricating grease composition comprises a base oil and a thickener, wherein the base oil comprises at least one perfluoropolyether, and the thickener comprises 5 mass% or more to 100 mass% or less of calcium carbonate, 0 mass% or more to 95 mass% or less of melamine cyanurate, and 0 mass% or more to 20 mass% or less of polytetrafluoroethylene for the total mass of the thickener.SELECTED DRAWING: None

Description

The present invention relates to lubricating grease compositions.

Power transmission parts such as gears and clutches, and feed screws such as slide screws and ball screws are required to have a stationary function to prevent changes in position when stationary, and grease with high static friction is required. Since this static function utilizes sliding contact, it causes friction and wear to the sliding member. Therefore, in order to prolong the life of mechanical parts, the grease is also required to have excellent wear resistance.

For example, Patent Document 1 discloses a grease composition having an excellent static function (high frictional force) by using melamine cyanurate and polytetrafluoroethylene as a solid lubricant, and calcium carbonate as a solid lubricant in Patent Document 2. It is disclosed that an object is obtained. Further, Patent Document 3 discloses a grease composition containing a perfluoropolyether oil as a base oil and using melamine cyanurate as a thickener.

However, in any of the patent documents, although lubrication properties due to sliding between resin members or sliding between resin members and metal members are evaluated, lubrication properties due to sliding between metal members are not mentioned. not Therefore, it is desired to develop a grease composition that exhibits sufficient lubricating performance even for sliding applications between metal members.

JP 2009-13351 A WO2018/030090 Japanese Unexamined Patent Application Publication No. 2017-20052

The present invention provides a lubricating grease composition that has a high static frictional force and excellent wear resistance in sliding between metal members.

A lubricating grease composition according to an embodiment of the present invention comprises a base oil and a thickener, wherein the base oil comprises at least one perfluoropolyether, and the thickener comprises all of the thickener. It contains calcium carbonate in an amount of 5% by mass to 100% by mass, melamine cyanurate in an amount of 0% by mass to 95% by mass, and polytetrafluoroethylene in an amount of 0% by mass to 20% by mass.

In one embodiment of the present invention, the average particle size of calcium carbonate is 30 μm or less.

In one embodiment of the present invention, the thickener contains more than 10% by mass and not more than 100% by mass of calcium carbonate with respect to the total mass of the thickener.

In one embodiment of the present invention, the content of polytetrafluoroethylene with respect to the total mass of the thickener is 0% by mass.

In one embodiment of the present invention, the average particle size of calcium carbonate is 10 μm or less, and the content of calcium carbonate is 100% by mass with respect to the total mass of the thickening, or the average particle size The content of melamine cyanurate with a diameter of 10 μm or less is more than 0% by mass and less than 90% by mass.

In one embodiment of the present invention, the lubricating grease composition is used for sliding portions between metal members.

ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide a lubricating grease composition that has a high static frictional force and excellent wear resistance when metal members slide against each other.

Embodiments of the present invention will be described below. The lubricating grease composition according to the present embodiment contains a base oil as a main component and a thickener, contains at least one perfluoropolyether as the base oil, and contains 5% by mass or more and 100% by mass as the thickener. It contains less than mass % of calcium carbonate. Moreover, as a thickening agent, melamine cyanurate of 0 to 95 mass % may be further included, and polytetrafluoroethylene of 0 to 20 mass % may be further included. A lubricating grease composition containing perfluoropolyether as a base oil is blended with calcium carbonate alone, or in addition to calcium carbonate, a thickener which may further contain a predetermined amount of melamine cyanurate and a predetermined amount of polytetrafluoroethylene. As a result, the lubricating grease composition is endowed with a high static function against sliding between metal members and excellent frictional properties. This makes it possible to obtain a lubricating grease composition that exhibits a high static frictional force and excellent wear resistance when metal members slide against each other. Hereinafter, each component contained in the lubricating grease composition according to this embodiment will be described in detail.

<Base oil>
In this embodiment, the base oil comprises at least one perfluoropolyether (PFPE). The perfluoropolyether may be linear or branched, and is not particularly limited. For example, a compound represented by the following formula (1) is preferably used.

In formula (1), CF ₂ O group, C ₂ F ₄ O group and C ₃ F ₆ O group are groups randomly bonded in the main chain, Rf is perfluoromethyl group, perfluoroethyl group, It is a perfluoro lower alkyl group having 1 to 5, preferably 1 to 3 carbon atoms such as a perfluoropropyl group. Further, x+y+z=3 to 200, and at least one of x, y and z may be 0. As the compound represented by formula (1), for example, perfluoropolyethers represented by the following formulas (2) to (5) can be used.

In formula (2), Rf is the same as defined in formula (1), and a=2-200. The compound represented by the formula (1) can be obtained by completely fluorinating a precursor produced by photo-oxidative polymerization of hexafluoropropylene, or by anionically polymerizing hexafluoropropylene under a cesium fluoride catalyst. It can be produced by treating an acid fluoride compound having a CF(CF ₃ )COF group with fluorine gas.

In formula (3), Rf is the same as defined in formula (1), b+c=3 to 200 and b:c=10:90 to 90:10. Compounds of formula (3) can be produced by complete fluorination of precursors produced by photo-oxidative polymerization of hexafluoropropene.

In formula (4), Rf is the same as defined in formula (1), d + e = 3 to 200, d: e = 10: 90 to 90: 10, preferably d / e > 1 be. The compound represented by formula (4) can be produced by complete fluorination of a precursor produced by photo-oxidative polymerization of tetrafluoroethylene.

In equation (5), f=2-100. The compound represented by formula (5) is a fluorine-containing polyether (CH ₂ CF ₂ CF ₂ O) _n obtained by anionic polymerization of 2,2,3,3-tetrafluorooxetane in the presence of a cesium fluoride catalyst. can be produced by fluorine gas treatment under ultraviolet irradiation at 160 to 300°C.

The perfluoropolyether as the base oil may be used alone or in combination of two or more. The kinematic viscosity (40° C.) of perfluoropolyether is not particularly limited, but preferably 10 to 2000 mm ² /sec, more preferably 10 to 1500 mm ² /sec. Examples of commercially available perfluoropolyethers include "FOMBLIM (registered trademark) M03" (40°C dynamic viscosity: 17 mm ² /sec) and "FOMBLIM (registered trademark) M15" (40°C dynamic viscosity) manufactured by Solvay Specialty Polymers Japan. Viscosity: 85 mm ² /s), “BARRIERTA J60 FLUID” manufactured by NOK Klüber (40° C. kinematic viscosity: 60 mm ² /s), etc. can be used.

The content of the base oil contained in the lubricating grease composition is preferably 50% by mass or more and 95% by mass or less, and 60% by mass or more and 90% by mass or less with respect to the total mass of the lubricating grease composition. is more preferable, and more preferably 70% by mass or more and 85% by mass or less.

<Thickener>
In the present embodiment, the thickener comprises calcium carbonate in an amount of 5% by mass or more and 100% by mass or less, preferably more than 10% by mass and 100% by mass or less, and 0% by mass or more of the total mass of the thickener. It contains 95% by mass or less of melamine cyanurate and 0% by mass or more and 20% by mass or less of polytetrafluoroethylene. Specifically, the thickener is preferably calcium carbonate, a mixture of calcium carbonate and melamine cyanurate, or a mixture of calcium carbonate and polytetrafluoroethylene. In particular, when the thickener contains more than 10% by mass and 100% by mass or less of calcium carbonate with respect to the total mass of the thickener, static friction force and wear resistance can be further improved. Also, the content of calcium carbonate may be 100% by mass with respect to the total mass of the thickening, thereby obtaining a lubricating grease composition remarkably excellent in static friction force and wear resistance.

The content of calcium carbonate contained in the lubricating grease composition is preferably 2% by mass or more and 50% by mass or less, and 5% by mass or more and 40% by mass or less with respect to the total mass of the lubricating grease composition. is more preferable, and more preferably 10% by mass or more and 30% by mass or less. The average particle size (primary particle size) of calcium carbonate is preferably 0.05 μm or more and 30 μm or less, more preferably 0.06 μm or more and 20 μm or less, and even more preferably 0.08 μm or more and 10 μm or less. . In particular, by using calcium carbonate having an average particle size of 10 μm or less, static friction can be improved.

Commercially available products of calcium carbonate include, for example, Shiraishi Calcium Co., Ltd. “Shiraenka PZ” (primary particle size: 0.08 μm), Sankyo Flour Milling Co., Ltd. “Escalon #3500” (average particle size: 1.0 μm), Sankyo Flour Milling. “Escalon First Class” (average particle size: 20 μm) manufactured by Sankyo Seifun Co., Ltd., “SFT-2000” (average particle size: 30 μm) manufactured by Sankyo Seifun Co., Ltd., and the like can be used.

When the thickener further contains melamine cyanurate, the content of melamine cyanurate is preferably more than 0% by mass and 95% by mass or less with respect to the total mass of the thickener, and more than 0% by mass and 90% by mass. It is more preferably less than mass %, and more preferably more than 0 mass % and 80 mass % or less. When the content of melamine cyanurate is less than 90% by mass with respect to the total mass of the thickener, the static friction force and wear resistance can be further improved.

The average particle size of melamine cyanurate is preferably 0.1 μm or more and 30 μm or less, more preferably 0.5 μm or more and 20 μm or less, and even more preferably 1.0 μm or more and 10 μm or less. In particular, by using melamine cyanurate having an average particle size of 10 μm or less, static friction can be improved.

The melamine cyanurate used is not particularly limited, and known melamine cyanurates can be used. Specifically, melamine cyanurate described in JP-B-45-5595, JP-B-61-34430, JP-A-05-310716, and JP-A-07-224049 is preferably used. be able to. In addition, commercially available products include, for example, Mitsubishi Chemical's "MCA-1", Nissan Chemical's "MC-860", "MC-4000", "MC-4500", "MC-6000", BASF "Melapur (registered trademark) MC 15" manufactured by the company can be used.

When the thickener further contains polytetrafluoroethylene (PTFE), the content of polytetrafluoroethylene is preferably more than 0% by mass and 10% by mass or less with respect to the total mass of the thickener, It is more preferably more than 0% by mass and 5% by mass or less. When the polytetrafluoroethylene content is 10% by mass or less with respect to the total mass of the thickener, the lubricating grease composition can be imparted with high static friction and excellent wear resistance. On the other hand, in a lubricating grease composition containing perfluoropolyether as a base oil and calcium carbonate as a thickener, the content of polytetrafluoroethylene with respect to the total mass of the thickener is 0% by mass. It is preferable not to contain polytetrafluoroethylene, which is used as a material, so that the static frictional force and wear resistance can be further improved.

The average particle size of polytetrafluoroethylene is preferably 0.1 μm or more and 50.0 μm or less, more preferably 0.1 μm or more and 10.0 μm or less. In addition, the polytetrafluoroethylene to be used is not particularly limited. A commercially available product such as DF PTFE" can be used.

The content of the thickener contained in the lubricating grease composition is preferably 5% by weight or more and 50% by weight or less, and is 10% by weight or more and 40% by weight or less with respect to the total weight of the lubricating grease composition. more preferably 15% by mass or more and 30% by mass or less.

In this embodiment, the lubricating grease composition may contain other additives within a range that does not affect its effect. As such additives, for example, known antioxidants, extreme pressure agents, rust inhibitors, corrosion inhibitors, viscosity index improvers, oiliness agents, etc. can be appropriately selected and contained. These additives may be used alone or in combination of two or more, and the type, blending amount, etc. can be arbitrarily determined according to the purpose of use.

Examples of antioxidants include phenolic antioxidants such as 2,6-di-t-butyl-4-methylphenol, 4,4′-methylenebis(2,6-di-t-butylphenol), alkyldiphenylamines, Amine-based antioxidants such as phenothiazine, alkylated phenyl-α-naphthylamine, phenothiazine, and alkylated phenothiazine are included.

Examples of extreme pressure agents include phosphorus compounds such as acidic phosphates, phosphites, and acidic phosphate amine salts, sulfur compounds such as sulfides and disulfides, chlorinated paraffins, chlorinated diphenyls, and the like. Chlorine-based compounds and metal organic compounds such as zinc dialkyldithiophosphate (ZnDTP) and molybdenum dialkyldithiocarbamate (MoDTP) can be mentioned.

Rust inhibitors include, for example, fatty acids, fatty acid soaps, alkylsulfonates, fatty acid amines, paraffin oxide, polyoxyethylene alkyl ethers, and the like.

Corrosion inhibitors include, for example, benzotriazole, benzimidazole, thiadiazole, and the like.

Viscosity index improvers include, for example, polymethacrylate, ethylene-propylene copolymer, polyisobutylene, polyalkylstyrene, hydrogenated styrene-isoprene copolymer, and the like.

Oily agents include, for example, fatty acids, higher alcohols, polyhydric alcohols, polyhydric alcohol esters, aliphatic esters, aliphatic amines, and fatty acid monoglycerides.

The lubricating grease composition according to the present embodiment can be produced by mixing the above base oil, thickener, and optionally other components using a normal mixing means. The mixing means is not particularly limited, but, for example, three rolls, a high-pressure homogenizer, and the like can be preferably used.

The lubricating grease composition according to the present embodiment has a high static friction force and a low wear depth in sliding between metal members, and is therefore suitable for use in sliding portions between metal members. Therefore, such a lubricating grease composition exhibits excellent lubricating performance in sliding between metal members.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and includes various aspects within the scope of the present invention, including all aspects included in the concept of the present invention and the scope of claims. can be modified to

Examples of the present invention will be described below, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded. Further, room temperature is assumed to be within the range of 20°C ± 5°C unless otherwise specified.

(Example 1)
Perfluoropolyether A (40° C. kinematic viscosity: 17 mm ² /s, product name “FOMBLIM (registered trademark) M03”, manufactured by Solvay Specialty Polymers Japan) 40 parts by mass and perfluoropolyether B (40° C. kinematic viscosity: 85 mm ² / s, product name “FOMBLIM (registered trademark) M15”, Solvay Specialty Polymers Japan Co., Ltd.) 40 parts by mass of base oil containing calcium carbonate A (average particle size: 1.0 μm, product name “ 20 parts by mass of Escalon #3500 (manufactured by Sankyo Seifun Co., Ltd.) was blended and stirred, followed by treatment with a three-roll mill to prepare a lubricating grease composition.

<Measurement and Evaluation of Abrasion Resistance>
Using an SRV tester, the obtained lubricating grease composition (sample oil) was applied onto a test piece, and a sliding test was performed under the following test conditions to measure the wear depth between metals. If the wear depth after the test is less than 2.0 μm, “◯”, if the wear depth is 2.0 μm or more and 3.0 μm or less, “△”, and if the wear depth exceeds 3.0 μm, the test It was automatically stopped before the end, and when it was impossible to measure, it was evaluated as "×", and when it was "Δ" or more, it was evaluated as excellent in wear resistance. Table 1 shows the evaluation results.

Upper test piece: SUJ2 metal ball (diameter 10 mm)
Lower test piece: Metal disk made of SUJ2 Load: 100N
Application amount of sample oil: 0.07 g
Frequency: 100Hz
Amplitude: 0.5mm
Temperature: Room temperature Time: 1 hour

<Measurement and Evaluation of Static Friction>
Using a reciprocating motion tester, the obtained lubricating grease composition (sample oil) was applied onto a test piece, and a sliding test was performed under the following test conditions to measure the static friction force between metals. If the static friction force at the fifth test start exceeds 500 g, it is evaluated as "◯", if the static friction force is 400 g or more and 500 g or less, it is evaluated as "△". If it is above, it was evaluated as having a high static friction force. Table 1 shows the evaluation results.

Upper test piece: S45C metal ball (diameter 10 mm)
Lower test piece: S45C metal plate Load: 3.5 kg
Application amount of sample oil: 0.15 g
Speed: 0.5 mm/sec Temperature: normal temperature Stroke: 10 mm

<Comprehensive evaluation>
If both wear resistance evaluation and static friction evaluation are "〇", "◎", one of the wear resistance evaluation and static friction evaluation is "〇" and the other is "△". If there is, "○", if both wear resistance evaluation and static friction evaluation are "△", "△", if either wear resistance evaluation or static friction evaluation is "×" was evaluated as "×".

(Example 2)
The amount of calcium carbonate A was changed to 10 parts by mass, and 10 parts by mass of melamine cyanurate A (average particle size: 2.0 μm, product name “MC-6000”, manufactured by Nissan Chemical Industries, Ltd.) was added as a thickener. A lubricating grease composition was prepared in the same manner as in Example 1, except that Table 1 shows the evaluation results.

(Example 3)
A lubricating grease composition was prepared in the same manner as in Example 1, except that the amount of calcium carbonate A was changed to 5 parts by mass, and 15 parts by mass of melamine cyanurate A was added as a thickener. Table 1 shows the evaluation results.

(Example 4)
A lubricating grease composition was prepared in the same manner as in Example 1, except that the amount of calcium carbonate A was changed to 2 parts by mass, and 18 parts by mass of melamine cyanurate A was added as a thickener. Table 1 shows the evaluation results.

(Example 5)
A lubricating grease composition was prepared in the same manner as in Example 2 except that calcium carbonate B (primary particle size: 0.08 μm, product name “Shiraenka PZ”, manufactured by Shiraishi Calcium Co., Ltd.) was used instead of calcium carbonate A. made. Table 1 shows the evaluation results.

(Example 6)
A lubricating grease composition was prepared in the same manner as in Example 2, except that calcium carbonate C (average particle size: 20 μm, product name “Escalon first grade”, manufactured by Sankyo Seifun Co., Ltd.) was used instead of calcium carbonate A. . Table 1 shows the evaluation results.

(Example 7)
Lubricating grease composition in the same manner as in Example 2 except that melamine cyanurate B (average particle size: less than 14 μm, product name “MC-4000”, manufactured by Nissan Chemical Industries, Ltd.) was used instead of melamine cyanurate A. made things. Table 1 shows the evaluation results.

(Example 8)
A lubricating grease composition was prepared in the same manner as in Example 5, except that calcium carbonate D (average particle size: 30 μm, product name: SFT-2000, manufactured by Sankyo Seifun Co., Ltd.) was used instead of calcium carbonate B. . Table 1 shows the evaluation results.

(Example 9)
The amount of calcium carbonate A was changed to 18 parts by mass, and polytetrafluoroethylene (average particle size: 4.0 μm, product name “Dynion (registered trademark) TF9207Z”, manufactured by 3M Japan) was added as a thickener by 2 masses. A lubricating grease composition was prepared in the same manner as in Example 1, except that parts were added. Table 1 shows the evaluation results.

(Comparative example 1)
The blending amount of perfluoropolyether A was changed to 42 parts by mass, the blending amount of perfluoropolyether B was changed to 43 parts by mass, and 15 parts by mass of melamine cyanurate A was added as a thickening agent instead of calcium carbonate A. A lubricating grease composition was prepared in the same manner as in Example 1, except that Table 2 shows the evaluation results.

(Comparative example 2)
A lubricating grease composition was prepared in the same manner as in Example 1, except that the amount of calcium carbonate A was changed to 15 parts by mass, and 5 parts by mass of polytetrafluoroethylene was added as a thickener. Table 2 shows the evaluation results.

(Comparative Example 3)
A lubricating grease composition was prepared in the same manner as in Example 2, except that polytetrafluoroethylene was used instead of melamine cyanurate A. Table 2 shows the evaluation results. The wear resistance was not measured or evaluated because it was evaluated as "x" in the evaluation of the static friction force.

(Comparative Example 4)
A lubricating grease composition was prepared in the same manner as in Example 3, except that polytetrafluoroethylene was used instead of melamine cyanurate A. Table 2 shows the evaluation results. The static friction force was not measured or evaluated because it was determined to be "x" in the wear resistance evaluation.

(Comparative Example 5)
The blending amount of perfluoropolyether A was changed to 39.5 parts by mass, and the blending amount of perfluoropolyether B was changed to 41 parts by mass. A lubricating grease composition was prepared in the same manner as in Example 1, except for adding 5 parts by mass. Table 2 shows the evaluation results.

(Comparative Example 6)
A lubricating grease composition was prepared in the same manner as in Example 1, except that 10 parts by mass of melamine cyanurate A and 10 parts by mass of polytetrafluoroethylene were added as thickeners instead of calcium carbonate A. Table 2 shows the evaluation results.

(Comparative Example 7)
Base oil containing 58 parts by mass of poly-α-olefin (kinematic viscosity at 40°C: 30 mm ² /s, product name “DURASYN (registered trademark) 166”, manufactured by Ineos Oligomers Japan) and barium complex soap as a thickener Sebacic acid and carboxylic acid monostearylamide are blended in a mixing vessel so that the amounts shown in Table 2 are blended, then heated and stirred at 80 to 130 ° C., barium hydroxide is added to perform a saponification reaction. , to form a barium composite soap. After the saponification reaction, 20 parts by mass of calcium carbonate A was added as a further thickening agent to the gel-like substance produced by cooling, and the mixture was stirred and treated with a three-roll mill to prepare a lubricating grease composition. Table 2 shows the evaluation results. The wear resistance was not measured or evaluated because it was evaluated as "x" in the evaluation of the static friction force.

Each component shown in Tables 1 and 2 is as follows. The value of each component in Tables 1 and 2 represents "parts by mass".

<Base oil>
・ Perfluoropolyether A: Product name “FOMBLIM (registered trademark) M03” (manufactured by Solvay Specialty Polymers Japan, 40° C. kinematic viscosity: 17 mm ² /s)
・Perfluoropolyether B: Product name “FOMBLIM (registered trademark) M15” (manufactured by Solvay Specialty Polymers Japan, 40° C. kinematic viscosity: 85 mm ² /s)
・Poly α-olefin: Product name “DURASYN (registered trademark) 166” (manufactured by Ineos Oligomers Japan, 40° C. kinematic viscosity: 30 mm ² /s)
<Thickener>
・ Calcium carbonate A: Product name “Escalon #3500” (manufactured by Sankyo Seifun Co., Ltd., average particle size: 1.0 μm)
・ Calcium carbonate B: Product name “Shiraenka PZ” (manufactured by Shiraishi Calcium Co., Ltd., primary particle size: 0.08 μm)
・ Calcium carbonate C: Product name “Escalon first grade” (manufactured by Sankyo Seifun Co., Ltd., average particle size: 20 μm)
・ Calcium carbonate D: product name “SFT-2000” (manufactured by Sankyo Flour Milling, average particle size: 30 μm)
・ Melamine cyanurate A: Product name “MC-6000” (manufactured by Nissan Chemical Industries, average particle size: 2.0 μm)
・ Melamine cyanurate B: product name “MC-4000” (manufactured by Nissan Chemical Industries, average particle size: less than 14 μm)
- Polytetrafluoroethylene: product name "Dynion (registered trademark) TF9207Z" (manufactured by 3M Japan, average particle size: 4.0 μm)
・Barium compound soap

From Table 1, in Examples 1 to 9, the lubricating grease composition contained a base oil containing perfluoropolyether, calcium carbonate alone or in addition to calcium carbonate, a predetermined amount of melamine cyanurate, a predetermined amount of poly and a thickening agent that may further include tetrafluoroethylene. Therefore, the obtained lubricating grease composition had high static frictional force and excellent wear resistance in sliding between metal members. In particular, in Examples 1 to 3 and 5 to 9 containing calcium carbonate in an amount of more than 10% by mass and 100% by mass or less with respect to the total mass of the thickener, the overall evaluation was "O", and higher lubrication performance was obtained. Indicated. In addition, in Example 1, calcium carbonate having an average particle size of 10 μm or less was used and the content of calcium carbonate was 100% by mass with respect to the total mass of the thickening. In Examples 2, 3, and 5 in which calcium is used and the content of melamine cyanurate having an average particle size of 10 μm or less with respect to the total mass of the thickening is more than 0% by mass and less than 90% by mass, the total The evaluation was "A", indicating a higher lubrication performance.

On the other hand, in Comparative Example 1 in which calcium carbonate was not used as a thickening agent and melamine cyanurate was used instead, the wear depth was high and the wear resistance was poor. Comparative Examples 2 and 3 in which calcium carbonate and polytetrafluoroethylene are used as the thickener, but the content of polytetrafluoroethylene exceeds 20% by mass with respect to the total mass of the thickener. In Comparative Example 4, where the content of polytetrafluoroethylene was 75% by mass with respect to the total mass of the thickener, the wear depth could not be measured, and the wear resistance was inferior to

In Comparative Example 5, in which calcium carbonate was not used as a thickener and polytetrafluoroethylene was used instead, the wear depth was high and the wear resistance was poor. Further, in Comparative Example 6, in which calcium carbonate was not used as a thickening agent and instead melamine cyanurate and polytetrafluoroethylene were used, the abrasion depth could not be measured, and the abrasion resistance was poor.

In Comparative Example 7, in which perfluoropolyether was not used as the base oil, synthetic hydrocarbon oil was used instead, and not only calcium carbonate but also barium complex soap was used as the thickener, a high static frictional force was obtained. I didn't get it.

The lubricating grease composition according to the present invention has a high static friction force and excellent wear resistance in sliding between metal members. It is effective for application to parts where contact between metal parts such as sliding bearings occurs.

Claims (6)

A lubricating grease composition containing a base oil and a thickener,
the base oil comprises at least one perfluoropolyether;
The thickener comprises 5% by mass or more and 100% by mass or less of calcium carbonate, 0% by mass or more and 95% by mass or less of melamine cyanurate, and 0% by mass or more and 20% by mass of the total mass of the thickener. % or less of polytetrafluoroethylene. 2. The lubricating grease composition according to claim 1, wherein the calcium carbonate has an average particle size of 30 [mu]m or less. 3. The lubricating grease composition according to claim 1 or 2, wherein the thickener contains more than 10% by mass and not more than 100% by mass of calcium carbonate relative to the total mass of the thickener. 4. The lubricating grease composition according to any one of claims 1 to 3, wherein the content of polytetrafluoroethylene relative to the total weight of said thickener is 0% by weight. The average particle size of calcium carbonate is 10 μm or less, and
The content of calcium carbonate is 100% by mass, or the content of melamine cyanurate having an average particle size of 10 μm or less is more than 0% by mass and less than 90% by mass with respect to the total mass of the thickening. A lubricating grease composition according to any one of claims 1 to 4. 6. The lubricating grease composition according to any one of claims 1 to 5, which is used for sliding parts between metal members.