JP5796834B2 - Grease composition for resin lubrication - Google Patents

Description

  The present invention relates to a resin grease composition, and more particularly to a resin grease composition applicable to a wide range of products such as gears and resin bearing parts of various machines and automobiles.

Resin (plastic) gears and sliding members are light, resistant to chemicals, do not rust, have low operating noise, and have self-lubricating properties. In addition, because of its excellent features such as being suitable for mass production and being able to produce at low cost, it has been widely used in various machines such as automobile parts, home appliances, electronic information equipment, and OA equipment in recent years. .
Various grease compositions have been proposed for the purpose of imparting lubricity to the surface of such resin members, and include, for example, base oils, thickeners, fluorosurfactants and styrenic block copolymers. Grease composition (Patent Document 1), non-oil-separable lubricant composition that prevents separation of oil by using a specific polymer material (Patent Document 2), grease that suppresses oil separation under high temperature conditions A composition (Patent Document 3) and the like have been proposed.

JP 2007-297422 A JP 2002-327188 A JP 2012-177105 A

  In a plastic gear used for an actuator for an automobile, grease is used for a gear meshing portion and a gear bearing portion as in the case of a metal gear. However, because it is for in-vehicle use, not only the lubrication performance itself but also the operability and startability in a low temperature environment such as -40 ° C. are regarded as important, and further, it is required that the hybrid vehicle and the electric vehicle can lower the voltage. . In addition, there are high demands for the reliability and long life of grease, and there is a demand for grease compositions that can satisfy all of these required performances.

  With regard to the startability in such a low temperature environment, it is important to use a low-viscosity base oil in order to reduce the voltage at the time of low temperature start, but since the amount of evaporation is large, it is not possible to satisfy the long life. On the other hand, if a high-viscosity base oil is used, the vaporization characteristics are improved and the life can be extended, but a high voltage is required at the time of starting at a low temperature. Thus, there is a problem that it is very difficult to achieve both improvement in startability in a low-temperature environment and extension of the life of grease.

  In addition, synthetic hydrocarbon oils (poly-α-olefins, etc.) are generally used as the base oil for resin-lubricating greases in order to avoid chemical attack on the resin material constituting gears and the like. However, synthetic hydrocarbon oil has a problem that compatibility with a thickener made of lithium soap is poor, oil separation phenomenon becomes large, product contamination due to oil oozing and gear quietness are impaired.

Furthermore, in general, a polybutylene terephthalate (PBT) resin pin integrally molded with the case material is used for the bearing portion of the gear installed in the actuator. Occurs and the glass fiber blended to increase the strength of the resin material is exposed from the surface of the member. The exposed hard glass fiber further causes abrasive wear, increasing the clearance between the gear and the bearing portion, thereby causing a problem of vibration and noise.
In addition, with the long-term use of the resin gear device, there is a problem that grease on the surface of the resin gear is removed from the contact surface, and the gears vibrate, leading to noise deterioration.

  Therefore, the present invention has been made in view of such a situation, and not only the lubrication characteristics required as a lubricant for resin (plastic) gear devices and the like, but also the improvement of startability particularly in a low temperature environment. An object of the present invention is to provide a grease composition that can improve wear resistance.

As a result of intensive studies to achieve the above object, the present inventors have used a low-viscosity base oil, and by using a styrene copolymer and / or liquid isoprene rubber as a thickener, it is excellent. It was found that low temperature startability and oil separation can be suppressed.
In addition, the use of polytetrafluoroethylene and melamine cyanurate as solid lubricants and the use of tricresyl phosphate or polymer esters as antiwear agents has been found to improve the wear resistance of resin bearings. It was.

That is, the present invention is a resin grease composition,
(A) a base oil comprising a polyalphaolefin oil and a kinematic viscosity at 100 ° C. of 4 to 6 mm ² / s,
(B) a thickener comprising lithium soap;
(C) a thickener,
(D) a solid lubricant, and (e) an antiwear agent, wherein the consistency of the composition is NLGI consistency No. 00, 0, 1 or 2, for resin The present invention relates to a grease composition.

The (c) thickener preferably includes one or both of a styrene isoprene resin and a liquid isoprene rubber.
Here, when the (c) thickener contains one of a styrene isoprene resin and a liquid isoprene rubber, the styrene isoprene resin is added in an amount of 0.5 to 6% by mass based on the total mass of the resin grease composition. The liquid isoprene rubber is preferably contained in a proportion of 5 to 12% by mass.
Alternatively, when the (c) thickener contains both a styrene isoprene resin and a liquid isoprene rubber, it is preferable that the weight ratio of the styrene isoprene resin to the liquid isoprene rubber be 2 to 5 at this time. It is preferable that the mixed thickening component of the styrene isoprene resin and the liquid isoprene rubber is included in a proportion of 0.9% by mass to 12% by mass based on the total mass of the grease composition.

The solid lubricant (d) preferably contains melamine cyanurate and polytetrafluoroethylene in a ratio in which the mass ratio of melamine cyanurate to polytetrafluoroethylene is 0.6 to 9, and at this time, the resin It is preferable that the mixed lubricating component of melamine cyanurate and polytetrafluoroethylene is contained at a ratio of 2% by mass to 10% by mass based on the total mass of the grease composition for use.
In particular, the solid lubricant (d) is preferably composed only of melamine cyanurate and polytetrafluoroethylene.

Further, the (e) antiwear agent preferably contains one or both of tricresyl phosphate and polymer ester. At this time, based on the total mass of the grease composition for resin, tricresyl phosphate and It is preferable to include either one or both of the polymer esters in a proportion of 0.5% by mass to 3% by mass.

The grease composition for resin of the present invention not only provides excellent lubrication characteristics for sliding parts such as resin gears and bearings, but also improves oil bleeding (oil separation) to the parts, In addition, startability (lower voltage) and wear resistance at low temperatures can be made excellent.
For this reason, the grease composition for resin of this invention can be used conveniently for sliding parts, such as an actuator of a motor vehicle, a bearing of OA apparatus, AV apparatus.

FIG. 1 is a conceptual diagram of a rheometer apparatus used for the rheometer measurement performed in the example. FIG. 2 is a conceptual diagram of an apparatus used in the wear test performed in the example.

  The grease composition for resin of the present invention contains (a) a base oil, (b) a thickener, (c) a thickener, (d) a solid lubricant, and (e) an antiwear agent. The consistency of an object is NLGI consistency number 00, 0, 1, or 2.

The base oil (a) used in the resin grease composition of the present invention is a low-viscosity synthetic hydrocarbon oil, and specifically comprises a polyalphaolefin oil (hereinafter also referred to as PAO). In the present invention, the base oil composed of the PAO is one having a kinematic viscosity at 100 ° C. of 4 to 6 mm ² / s.
In the present invention, when the viscosity of the base oil is larger than the above numerical range, the torque performance at low temperatures is inferior, and when it is smaller than the above numerical range, the amount of evaporation at high temperatures increases, which is not preferable.

  The (a) base oil is preferably contained in a proportion of 70% by mass to 90% by mass based on the total mass of the resin grease composition of the present invention.

  The resin grease composition of the present invention uses (b) lithium soap as a thickener.

The (b) thickener is preferably contained in a proportion of 3% by mass to 15% by mass based on the total mass of the resin grease composition of the present invention.
The resin grease composition of the present invention has a blending amount of (a) the base oil and (b) the thickener so that the NLGI consistency number is 00, 0, 1, or 2. Adjust as appropriate.

  In the grease composition for resin of the present invention, (c) the thickener can be a polymer or the like normally used in a grease composition, and in particular, the effect as a thickener and the apparatus when used as a grease composition Considering the effect on the low temperature startability and durability of the resin, it is particularly preferable to use a styrene isoprene resin or a liquid isoprene rubber.

As the styrene isoprene resin, those having a number average molecular weight of 100,000 to 200,000 can be suitably used, and those having a higher molecular weight are more effective as a thickener.
The styrene isoprene resin used in the present invention is not particularly limited as long as it has the above-mentioned number average molecular weight, and can be suitably used, but specific examples include, for example, JSR SIS 5200 manufactured by JSR Corporation. 5405, 5505; Lubrizol (registered trademark) 7306, 7308, 7460 manufactured by Lubrizol; Infineum (registered trademark) SV140, SV150, SV160 manufactured by Infinium Japan Co., Ltd .; manufactured by Kuraray Co., Ltd. Septon (registered trademark) 1001, 1020 and the like.

Further, as the liquid isoprene rubber, it is preferable to use a homopolymer type polymer composed of only a single molecule of isoprene. Copolymer-type liquid isoprene rubber containing butadiene is not preferable because it may cause thermosetting by heating, that is, when it is blended in a grease composition, it may cause problems such as solidification of the grease and deterioration of mobility.
The liquid isoprene rubber (homopolymer) preferably has a number average molecular weight in the range of about 28,000 to 54,000. In general, if a large amount of those having a number average molecular weight exceeding 100,000 is contained, there is a risk of solidification, and the dispersibility in the base oil is deteriorated.
The liquid isoprene rubber used in the present invention is not particularly limited as long as it has the above-mentioned properties, and can be suitably used, but specific examples include, for example, Kuraray Kuraprene (registered trademark) LIR- 30, LIR-50, LIR-200, LIR-290; ISOLENE 40 manufactured by ROYAL ELASTOMERS, 400, and the like.

When the styrene isoprene resin or the liquid isoprene rubber is used alone as the thickener (c), the styrene isoprene resin is 0.5% by mass to 6% by mass based on the total mass of the resin grease composition of the present invention. It is preferable that it is contained in a proportion, more preferably in a proportion of 2% by mass to 4% by mass. The liquid isoprene rubber is preferably contained in a proportion of 5% by mass to 12% by mass, more preferably in a proportion of 5% by mass to 8% by mass, based on the total mass of the grease composition for resin of the present invention.
When the styrene isoprene resin and the liquid isoprene rubber are used in combination as the thickener (c), the ratio of the mass ratio of the styrene isoprene resin to the liquid isoprene is 2 to 5, that is, styrene isoprene resin / liquid isoprene rubber = 2. It is preferable to use together in the mass ratio of thru | or 5. And based on the total mass of the grease composition for resin of the present invention, the mixed thickening component of the styrene isoprene resin and the liquid isoprene rubber is in a ratio of 0.9 mass% to 12 mass%, more preferably 0.9 mass. It is preferable to contain in the ratio of% to 6 mass%.

  In addition, polybutene, polyisobutene, polyisobutylene, etc. can be used in combination as a thickener. However, it is desirable to refrain from using polyalphaolefins such as PAO100 having high viscosity, alphaolefin copolymers (AOCP), or the like because of an increase in viscosity at low temperatures.

In the resin grease composition of the present invention, it is preferable that (d) the solid lubricant is a combination of melamine cyanurate and polytetrafluoroethylene. In particular, it is preferable to use only melamine cyanurate and polytetrafluoroethylene from the viewpoint of most suitably exerting the effects of the present invention.
These are preferably used in combination at a mass ratio of melamine cyanurate to polytetrafluoroethylene of 0.6 to 9, that is, melamine cyanurate / polytetrafluoroethylene = 0.6 to 9. . The mixed lubricating component of melamine cyanurate and polytetrafluoroethylene is preferably contained at a ratio of 2% by mass to 10% by mass based on the total mass of the resin grease composition of the present invention.
In addition, in the range which does not impair the effect of this invention, you may mix | blend a solid lubricant known in the said technical field, such as calcium carbonate and molybdenum disulfide, as (d) solid lubricant.

In the grease composition for resin of the present invention, it is preferable that (e) the antiwear agent includes one or both of tricresyl phosphate and a polymer ester.
Examples of the polymer ester include esters of aliphatic monovalent carboxylic acids and divalent carboxylic acids with polyhydric alcohols. Specific examples of the polymer ester include, but are not limited to, PRIOLUBE (registered trademark) series manufactured by Claude Japan.
And it is preferable to contain 0.5 mass% thru | or 3 mass% of one or both of these tricresyl phosphate and polymer ester based on the gross mass of the grease composition for resins of this invention.

In addition, the resin grease composition of the present invention is known in the technical field such as an antioxidant, a rust preventive, an extreme pressure agent, an oil improver, and a corrosion inhibitor within a range not impairing the effects of the present invention. Various additives may be appropriately selected and blended.
For example, as an antioxidant, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) ) Propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, 1,3,5-trimethyl- 2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate ], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylene [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamide), etc. Examples include hindered phenol antioxidants.
These antioxidants may be used singly or in combination of two or more, and usually a proportion of 0.01% by mass to 5% by mass based on the total mass of the resin grease composition It is preferable to add at.

  As described above, the grease composition for a resin of the present invention has an NLGI consistency number of 00, 0, 1 or 2 (that is, within the range of about 430 to 260 in the range of the penetration consistency). is there. When the grease composition is softer than this, grease leaks during use, and when it is hard, the grease hardly remains on the contact surface.

  The resin of the resin member to be lubricated using the resin grease composition of the present invention includes polyethylene (PE), polypropylene (PP), ABS resin (ABS), polyacetal (POM), nylon (PA), polycarbonate (PC). , Phenol resin (PF), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyether sulfone (PES), polyimide (PI), polyether ether ketone (PEEK) and the like.

  The resin grease composition according to the present invention includes office machine parts such as copying machines and printers, speed reducers / speed increasers, power transmission devices such as gears, chains, and motors, travel system parts, control system parts such as ABS, Steering system parts, drive system parts such as transmissions, automotive reinforcement parts such as power window motors, power seat motors and sunroof motors, electronic information equipment, hinge parts such as mobile phones, food / pharmaceutical industries, steel, construction, and glass industries It can be widely applied to various parts in the cement industry, film tenter, chemical / rubber / resin industry, environment / power equipment, paper / printing industry, wood industry, textile / apparel industry, and mechanical parts that move relative to each other. The present invention is also applicable to rolling bearings, thrust bearings, dynamic pressure bearings, resin bearings, linear motion device bearings, and the like.

In particular, the resin grease composition of the present invention can be effective in reducing noise, which is a problem in automobile actuators and the like.
As an example, the actuator includes a stepping motor, a gear device including at least a plurality of stages of gears that sequentially decelerates the rotation of the stepping motor to increase rotational torque, and a base member in which these are installed. At this time, when the stepping motor rotates, the vibration generated by the stepping motor finally gathers at the meshing location of the first gear and the second gear, and generates a large periodic sound at the meshing location. Further, since the first stage gear and the second stage gear have different rotational directions, there is a difference between their vibration and sound pressure, and the vibration sound in the rotational direction where the vibration sound pressure is large is heard as noise. Further, a gap is generated due to wear of the bearing portion, which also causes vibration and noise.
In addition, since the actuator is assumed to operate in a low temperature environment, the influence on the starting torque due to the increase in the viscosity of the grease at the low temperature starting cannot be ignored.
The grease composition for resin of the present invention can be used not only for reducing noise but also for extending the product life by using it for gear meshing parts, gear bearing parts, and the like.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to this.

Details and abbreviations of each component used for preparing the greases of the following examples and comparative examples are as follows.
(A) Base oil / PAO: polyalphaolefin (kinematic viscosity at 100 ° C .: 4 mm ² / s)
(B) Thickener, Li soap: 12 hydroxy lithium stearate (c) Thickener, SIP: Styrene isoprene resin (Infineum (registered trademark) SV150)
LIR: Liquid isoprene rubber (Kuraprene (registered trademark) LIR-50)
(D) Solid lubricant / PTFE: Polytetrafluoroethylene (particle size: 10 to 25 μm)
MCA: Melamine cyanurate (particle size 15-30 μm)
(E) Antiwear agent / TCP: tricresyl phosphate / polymer ester: PRILOBE (registered trademark) 3986 manufactured by CRODA JAPAN
(Other additives)
Hindered phenol antioxidant: pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]

[Preparation of grease composition]
(A) Base oil and (b) thickener are heated and stirred, dissolved in the blending amounts shown in the following tables, and then cooled, where (c) thickener, (d) solid lubricant, ( e) Antiwear agent and antioxidant were added and homogenized with a roll mill to prepare grease compositions of Examples 1 to 20 and Comparative Examples 1 to 9.
The resulting grease composition was evaluated for the penetration, oil separation, rheometer measurement (starting torque evaluation) and wear resistance (bearing part wear) using the following procedures.

(1) Mixing penetration (JIS K2220 7.)
It evaluates the external hardness of the grease and can be said to correspond to the viscosity of the lubricating oil.
Test temperature: 25 ° C
Test method: JIS K2220 In accordance with the above, the mixing penetration was measured according to the procedure of the mixing penetration test using a standard cone.

(2) Oil separation test (JIS K2220 11.)
The degree of oil separation evaluates the oil separation tendency of grease under static conditions.
The degree of oil separation was measured by taking 20 g of each grease composition as a sample on a filter using a circular wire mesh, hanging it in a beaker with a known weight, and placing it in a constant temperature bath (100 ° C.) for a specified time (24 hours). ), And after standing to cool, the weight of the separated oil in the beaker is measured and calculated as mass% with respect to the sample. The mass% of the obtained separated oil was evaluated according to the following criteria. When the value of the mass% of the separated oil is high (the oil separability of the grease is large), the storage stability is poor and it is inconvenient for long-term use such as a bearing.
-Temperature: 100 ° C Time: 24 hours [Evaluation: Mass% of separated oil]
0% by mass to 7% by mass: ○ Usable over 7% by mass ~: × Not usable

(3) Rheometer measurement After setting the gap between the upper rotating plate and the lower fixed plate using the rheometer device shown in FIG. 1, and holding each grease composition between the gaps and keeping it in an environment of −40 ° C. The torque at startup (low temperature startup torque) was measured under conditions where the shear rate was 10 s ⁻¹ . The value of the measured low temperature starting torque was evaluated according to the following criteria.
・ Measuring device: Rheometer (see Fig. 1)
・ Measurement temperature: -40 ℃
・ Gap of plate: 0.5mm
-Shear rate: 10 s ^-1
[Evaluation: Low temperature starting torque]
7 mN · m or less: ○ Excellent in low-temperature startability 10 mN · m or less: Δ Slightly inferior in low-temperature startability Over 10 mN · m: × Inferior in low-temperature startability

(4) Wear test evaluation As shown in the conceptual diagram of the wear test in FIG. 2, a load test using a resin shaft and a resin cylindrical block was performed to evaluate the wear resistance (bearing portion wear).
[Measurement condition]
・ Resin shaft Shaft diameter: 4mm in diameter, resin material: Glass filler-30% blend Polybutylene terephthalate (PBT)
-Resin cylindrical block: diameter 10 mm, resin material: polyacetal (POM) (no glass filler)
-Load: 30 Ncm Temperature: Room temperature (about 25 ° C)
・ Axis peripheral speed 20rpm 4.2mm / s
・ Test time: 500 hours [Procedure]
Each grease composition was applied to the outer peripheral surface of the resin shaft shown in FIG. 2 (conceptual diagram), and then the resin shaft was inserted into a resin cylindrical block. A weight (load load) was applied to the cylindrical block to apply a load, and the resin shaft was connected to a rotating machine (not shown) and rotated. After rotating under the conditions shown in the above measurement conditions, the outer peripheral surface of the resin shaft in contact with the cylindrical block was observed.
[Evaluation]
After the endurance test, the state of wear of the outer peripheral surface of the resin shaft in contact with the cylindrical block was visually observed and evaluated according to the following evaluation criteria.
○: No wear ×: Wear (glass fiber bare)

[Example 1 to Example 6, Comparative Example 1 and Comparative Example 2]
The grease compositions of Examples and Comparative Examples in which the addition amount of styrene isoprene resin (SIP) was variously changed were prepared and subjected to various evaluations. The obtained results are shown in Table 1.

  As shown in Table 1, although the oil separation degree is improved as the content of the thickener (c) styrene isoprene resin is increased, the viscosity is increased and the low temperature starting torque is deteriorated. As the content of isoprene resin decreased, the degree of oil separation deteriorated, while the viscosity decreased and the effect on the low temperature starting torque was small.

[Examples 7 to 9, Comparative Example 3 and Comparative Example 4]
The grease compositions of Examples and Comparative Examples in which the addition amount of liquid isoprene rubber (LIR) was variously changed were prepared and subjected to various evaluations. The obtained results are shown in Table 2.

As shown in Table 2, as with the results of the styrene isoprene resin, an increase in the oil separation degree and a deterioration in the low temperature starting torque were observed with an increase in the addition amount of the liquid isoprene rubber, and an oil separation degree with a decrease in the addition amount. Worsening and improvement in low temperature starting torque were observed.

[Examples 10 to 13]
The grease composition of the Example which used styrene isoprene resin (SIP) and liquid isoprene rubber (LIR) together, and changed each addition amount variously was prepared, and various evaluation was performed. The obtained results are shown in Table 3.

  As shown in Table 3, by using a combined ratio of styrene isoprene resin / liquid isoprene rubber in a mass ratio of 2 to 5 and total addition amount of 0.9 to 12% by mass, grease that generally satisfies the evaluation items A composition was obtained.

[Example 1 (reprinted) and Examples 14 to 17]
The grease composition of the Example which changed the combined ratio of polytetrafluoroethylene (PTFE) and melamine cyanurate (MCA) variously was prepared, and various evaluation was performed. Table 4 shows the obtained results.

  As shown in Table 4, when the combined ratio of melamine cyanurate / polytetrafluoroethylene is in the range of 0.6 to 9 in terms of mass ratio, and the total addition amount thereof is 2 to 10% by mass, all evaluations are made. A grease composition satisfying the items was obtained.

[Example 1 (reprinted) and Examples 18 to 20 and Comparative Example 9]
Grease compositions of Examples and Comparative Examples with various blending ratios of tricresyl phosphate (TCP) or polymer ester were prepared, and various evaluations were performed. The results obtained are shown in Table 5.

  As shown in Table 5, the grease composition of the example to which tricresyl phosphate or polymer ester was added was excellent in wear resistance, but Comparative Example 9 not containing these was inferior in wear resistance. Got.

  As described above, as shown in Tables 1 to 5, in the resin grease compositions of Examples 1 to 20, (c) by adding liquid isoprene rubber and / or styrene isoprene resin as a thickener at a low temperature. It was confirmed that there was an effect on startability and durability (reduction of shaft wear). Moreover, when the addition amount of a thickener was made to increase from a suitable range, the result that the viscosity in low temperature will increase and starting property will deteriorate was obtained.

  Although the best embodiment has been described in detail above, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention. is there.

Claims (4)

In resin grease composition,
(A) a base oil comprising a polyalphaolefin oil and a kinematic viscosity at 100 ° C. of 4 to 6 mm ² / s,
(B) a thickener comprising lithium soap;
(C) a thickener containing one or both of a styrene isoprene resin and a liquid isoprene rubber ,
(D) a solid lubricant containing melamine cyanurate and polytetrafluoroethylene , and (e) an antiwear agent, the consistency of the composition being NLGI consistency number 00, 0, 1 or 2 der is,
When the styrene isoprene resin or liquid isoprene rubber is used alone, based on the total mass of the composition, the styrene isoprene resin is used in a proportion of 0.5% to 6% by mass, or the liquid isoprene rubber is used in an amount of 5% to 5%. Containing 12% by weight, or
When the styrene isoprene resin and the liquid isoprene rubber are used in combination, based on the total mass of the composition, the mixed thickening component of the styrene isoprene resin and the liquid isoprene rubber is included in a proportion of 0.9% by mass to 12% by mass, And
A grease composition for a resin comprising a mixed lubricating component of melamine cyanurate and polytetrafluoroethylene in a proportion of 2% by mass to 10% by mass based on the total mass of the composition. Wherein (d) the solid lubricant is characterized containing-law and the melamine cyanurate and polytetrafluoroethylene in proportions by weight ratio of melamine cyanurate for polytetrafluoroethylene is 0.6 to 9, claim The grease composition according to 1 . The grease composition according to claim 2 , wherein (d) the solid lubricant is composed of melamine cyanurate and polytetrafluoroethylene. The (e) antiwear agent contains one or both of tricresyl phosphate and polymer ester,
Based on the total weight of the resin grease composition, characterized in that it contains either the rate of one or both 0.5 wt% to 3 wt% of tricresyl phosphate and polymer esters, in claim 1 The grease composition as described.