JP2011046873A - Grease composition and motion guide device lubricated with the grease composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grease composition having a low production cost, low dusting properties, and provides an oil film strength and to provide a motion guide device lubricated with the grease composition. <P>SOLUTION: The grease composition includes a base oil and a thickening agent, wherein the base oil is an ester oil or a fluorine-free ether oil, and the thickening agent is one having self-lubricating properties. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a grease composition and a motion guide device lubricated with the grease composition.

  Grease enclosed as a lubricant in motion guide devices (linear guides, ball screws, rolling bearings, etc.) incorporated in devices that require a clean environment, such as semiconductor manufacturing devices, liquid crystal manufacturing devices, electronic computers, and printed circuit board manufacturing devices As the grease, the oil scattering at the lubrication portion is reduced, that is, the dust generation property is preferably used.

As such grease, grease using perfluoropolyether (PFPE) as a base oil and polytetrafluoroethylene (PTFE) having a specific particle size as a thickener is used (Patent Document 1). . PFPE has generally been used under vacuum because of its low vapor pressure. However, since PFPE has a high viscosity, it has high rolling resistance and low oil film strength, so there is room for improvement in terms of heat generation and wear resistance of the lubricating member. Also, PFPE used as a base oil is expensive, and the use of PFPE for the production of grease increases the production cost.
On the other hand, as a grease with excellent dust generation properties, the base oil is ester oil, the thickener is grease using an aliphatic diurea compound, the base oil is ether-based oil, and the thickener is metal lithium soap. Grease is also known (Patent Document 2).
In addition, as a technique for suppressing problems caused by dust generation, conventionally, there are known techniques for improving the sealing performance of a ball screw nut provided in a motion guide device or for removing fine particles generated by attaching a tube to the nut. Yes.

JP 2008-37892 A JP-A-2005-272768

  The present invention provides a grease composition that is low in production cost, excellent in low dust generation and high in oil film strength as compared with a commercially available low dust generation grease, and a motion guide device lubricated with the grease composition.

The present invention relates to the following grease composition.
A grease composition containing a base oil and a thickener, wherein the base oil contains an ester oil or an ether oil containing no fluorine, and the thickener contains a thickener having a self-lubricating property. Composition.

  According to the present invention, a grease composition that is low in production cost, superior in low dust generation property and high in oil film strength as compared with conventionally available low dust generation grease, and a motion guide device lubricated with the grease composition Can be obtained.

It is a figure which shows the 1st form of the movement guide apparatus which can apply the grease of this invention. It is a figure which shows the 2nd form of the movement guide apparatus which can apply the grease of this invention. It is a 1st figure which shows the result of the dust generation amount measurement. It is a 2nd figure which shows the result of the dust generation amount measurement. It is a 1st figure which shows the result of dust generation amount measurement. It is a 2nd figure which shows the result of dust generation amount measurement. 2 is a diagram showing a vapor pressure curve of grease 1. FIG.

  Hereinafter, the present invention will be specifically described as embodiments, but the present invention is not limited thereto.

<Base oil used in this embodiment>
The grease composition of the present embodiment contains an ester oil shown below or an ether oil containing no fluorine as a base oil. The grease composition of the present embodiment may contain a base oil other than an ester oil or a fluorine-free ether oil as a base oil. When a base oil other than an ester oil or an ether oil not containing fluorine is included as the base oil, the content of the base oil is 10 wt. % Or less, and more preferably 5% by weight or less.
The kinematic viscosity at 40 ° C. of the base oil used in the grease composition of the present embodiment is preferably 60 to 120 mm ² / s from the viewpoint of improving the lubricating performance and the reduction of oil scattering, and preferably 90 to 110 mm. ² / s. The kinematic viscosity at 100 ° C. of the base oil is 10-50.
It is preferable from the viewpoint of improving the reduction in lubricating performance and oil splashing be mm ² / s, particularly preferably 10 to 20 mm ² / s.
This kinematic viscosity can be measured by using a method defined in JIS K 2220.
(1) Ester oil Examples of ester oils include aliphatic hydrocarbon ester oils. More specifically, the ester oil is at least one selected from the following general formulas (1) to (5). These ester oils are preferably 60% by weight or more, and particularly preferably 90% by weight or more, based on the total ester oil.
(1) a diester synthetic oil represented by R ³ OCO (CH ₂ ) _n COOR ⁴ ;
(Wherein, ^{R 3} and ^{R 4} may be the same or different, represents an aliphatic hydrocarbon group having 3 to 18 carbon atoms, n represents shows 3-12)
(2) a triester synthetic oil represented by C ₂ H ₅ C (CH ₂ OCOR ⁵ ) ₃ ;
(In the formula, three R ^{5 s} may be the same or different and represent an aliphatic hydrocarbon group having 3 to 10 carbon atoms)
(3) a tetraester synthetic oil represented by C (CH ₂ OCOR ⁶ ) ₄ ,
(Wherein, four R ^{6 s} may be the same or different and represent an aliphatic hydrocarbon group having 3 to 10 carbon atoms)
(4) Dipentaerythritol-based synthetic oil represented by C (CH ₂ OCOR ⁷ ) ₃ CH ₂ OCH ₂ C (CH ₂ OCOR ⁷ ) ₃ , and (wherein 6 R ⁷ may be the same or different) Well, an aliphatic hydrocarbon group having 3 to 10 carbon atoms)
(5) Other neopentyl polyol ester synthetic oils.
(The hydrocarbon group of the acyl group represents an aliphatic hydrocarbon group having 3 to 10 carbon atoms)

Examples of the diester synthetic oil represented by the general formula (1) include di-2-ethylhexyl sebacate, di-2-ethylhexyl azelate, di-2-ethylhexyl adipate and the like represented by the general formula (2). Examples of the triester-based synthetic oil include trimethylolpropane carboxylic acid ester, and examples of the tetraester-based synthetic oil represented by the general formula (3) include pentaerythritol carboxylic acid ester represented by the general formula (4). Examples of dipentaerythritol synthetic oils include dipentaerythritol carboxylic acid esters, and other neopentyl polyol ester synthetic oils represented by the general formula (5) include neopentyl polyol carboxylic acid esters. .

(2) Fluorine-free ether oil The fluorine-free ether oil used in the present invention can be used without particular limitation as long as it is a compound that does not contain a fluorine element and has an ether group.
As such an ether oil, any commercially available aromatic ring having 2 to 5 aromatic rings and having an ether group can be used. However, as the number of rings increases, the cost increases accordingly. For this reason, alkyl-substituted diphenyl ethers, triphenyl ethers, and tetraphenyl ethers having 2 to 4 aromatic rings and having an alkyl group having 10 to 20 carbon atoms are preferably used. The alkyl-substituted diphenyl ether represented by 1) is particularly preferred. The alkyl-substituted diphenyl ether is preferably 60% by weight or more, particularly preferably 90% by weight or more, based on the entire ether oil.

（式中、Ｒ^１及びＲ^２は、炭素数１０〜２０の炭化水素基であり、Ｒ^１及びＲ^２は互いに同一であっても異なるものであってもよい。また、ｍ及びｎは１≦ｍ＋ｎ≦４の関係を満たし、０以上の整数を示す。）

(Wherein, ^{R 1} and ^{R 2} is a hydrocarbon group having 10 to 20 carbon atoms, ^{R 1} and ^{R 2} may be of different, even the same. Further, m and n are 1 ≦ m + n ≦ 4 is satisfied, and an integer of 0 or more is shown.)

Examples of R ¹ and R ² include decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, ntadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and eicosyl group. Is preferably an alkyl group having 10 to 18 carbon atoms, particularly preferably an alkyl group having 12 to 16 carbon atoms.
Moreover, about the range of the said m + n, 2-4 can be mentioned.

  The grease composition of the present embodiment preferably contains 40 to 80% by weight, more preferably 40 to 60% by weight of the above ester oil or ether oil not containing fluorine as the base oil. When the content of the base oil is within the above range, a grease with less oil scattering can be obtained while ensuring high lubricity.

<Thickener used in this embodiment>
Thickeners used in the present invention include those having a thickening action and self-lubricating properties. A thickener having a thickening action and self-lubricating property can be used without particular limitation. The ratio of the thickener and the self-lubricating agent contained in the total thickener is preferably 95% by weight or more, and particularly preferably 100% by weight. As a thickener other than the thickener having a thickening action and self-lubricating property that can be used in the present embodiment, those conventionally used can be used without particular limitation. The self-lubricating action in the present embodiment means that when the thickener itself, which is an organic polymer compound, is subjected to mechanical shearing, the bonds between the crystal planes are easily broken and the lubricating function is exhibited. . Using a thickener and a self-lubricating agent as a thickener and combining it with the above specific base oil has never been known so far. Has an excellent effect.

Specific examples of the thickener having a thickening action and self-lubricating property include polytetrafluoroethylene (hereinafter also referred to as PTFE).
The polytetrafluoroethylene preferably has an average primary particle size of 0.5 μm or less from the viewpoint of securing the oil film thickness, more preferably 0.1 to 0.5 μm, and 0.1 to 0. Particularly preferred is 2 μm. If the thickness is less than 0.1 μm, the primary particles may aggregate to make the oil film thickness non-uniform, and if the thickness exceeds 0.5 μm, the filling of the particles becomes insufficient and the oil film thickness may become non-uniform. Such a polytetrafluoroethylene is, as an example of a commercial product, Daikin Industries, Ltd. Lubron L2, Mitsui DuPont Fluorochemical Co., Ltd. TL
P10F-1 DuPont Zonyl MP 1600N etc. are mentioned.
The average primary particle size of the thickener can be determined by “particle measurement method by laser diffraction method” based on ISO 13320-1.

The grease composition of the present embodiment preferably contains 20 to 60% by weight of a thickener, more preferably 30 to 60% by weight, and particularly preferably 40 to 50% by weight.
When the content of the thickener is 60% by weight or less, the consistency of the grease composition of the present embodiment, which will be described later, is improved, thereby improving the lubricity and being 20% by weight or more. A grease excellent in low dust generation can be obtained.
Moreover, in the grease composition of this embodiment, each content is adjusted so that the ratio of the content of the base oil and the thickener is 0.67 to 1 when the base oil is 1 by weight. This is preferable from the viewpoint of obtaining a grease composition with less oil scattering while ensuring high lubricity.

<Grease composition of this embodiment>
In the grease composition of the present embodiment, the consistency at 25 ° C. is preferably 200 to 260 from the viewpoint of suppressing oil scattering, and particularly preferably 210 to 240.
This consistency can be measured by using a method defined in JIS K 2220.
The consistency of the grease composition can be adjusted by adjusting the content of the thickener described below.

Various additives can be added to the grease composition of the present embodiment as necessary, as shown below.
Examples of such additives include antioxidants (for example, amine antioxidants), rust inhibitors (for example, succinic acid rust inhibitors), metal corrosion inhibitors, oil agents, antiwear agents, and poles. Although a pressure agent etc. are mentioned, what does not contain a metal component is preferable.
The grease composition of the present embodiment can be easily produced by mixing the above components and other additives in a desired blending ratio.

  In the present embodiment, by using a grease composition that combines the base oil and the thickener as described above, not only can the manufacturing cost be reduced and the amount of dust generated can be reduced, but also high oil film strength can be obtained. all right.

  The grease composition of the present embodiment is not particularly limited, but is used, for example, to impart lubricity in a motion guide device. More specifically, a rolling element (ball or roller), a raceway shaft (rolling rail, screw shaft, etc.) having a rolling surface on which the rolling element rolls, and a load on the rolling element relative to the rolling surface. A moving member (track rail, nut member, etc.) that has a rolling surface and is provided on the shaft via the rolling element and relatively reciprocates along the shaft, for example, a linear guide, a ball Used in motion guide devices such as screws and ball splines.

And when using the grease composition of this embodiment, the rolling surface of the track shaft of a motion guide apparatus and the load rolling surface of a moving member are lubricated. The method and means for lubricating the motion guide device using the grease composition of the present embodiment are not particularly limited.

For example, a linear guide which is a linear guide device will be described as an example as follows.
That is, as shown in FIG. 1, the linear guide is reciprocally mounted via a track rail (1) installed as a shaft and balls (3) installed as a number of rolling elements on the track rail. And a moving block (2) as a moving member.
The track rail has a substantially rectangular cross section perpendicular to the longitudinal direction thereof, and rolling surface rolling grooves (1a) serving as a track when the ball rolls are formed on the surface (near both upper and both side surfaces). 1
b) is formed over the entire length in the longitudinal direction of the track rail.
On the other hand, the moving block is composed of a moving block main body portion made of a metal material and a pair of end plates (5) made of a resin material installed on both end surfaces of the moving block main end in the moving direction.
Loaded rolling element rolling grooves (4a, 4b) are provided at positions corresponding to the rolling element rolling grooves of the track rail in the moving block main body. A rolling element rolling path is formed by the rolling element rolling groove of the track rail and the loaded rolling element rolling groove formed in the main body of the moving block, and a plurality of balls introduced into this passage roll while receiving a load. Will do. Moreover, the moving block main-body part is provided with the unloaded rolling-element rolling path extended in parallel with a load rolling-element rolling groove. Further, each of the pair of end plates is provided with a direction changing path that connects each unloaded rolling element rolling path and each loaded rolling element rolling path. One infinite circuit is constituted by a combination of one loaded rolling element rolling path and an unloaded rolling element rolling path and a pair of direction changing paths connecting them.
A plurality of balls are installed in an infinite circulation path composed of a loaded rolling element rolling path, an unloaded rolling element rolling path, and a pair of direction changing paths so as to be capable of infinite circulation. Reciprocal movement is possible.

  An end seal (6) whose tip is in sliding contact with the track rail (1) is provided on the outer surface of each end plate 5, and the tip of the moving block (2) is track rail (1). ) And a side seal (8) whose tip abuts against the side surface of the track rail (1). These end seal (6), inner seal (7) and side seals are provided. The seal (8) forms a sealed space for enclosing the grease composition between the left and right shoulders of the track rail (1) and the corresponding left and right corners of the slide base (2). One end plate (5) is provided with a grease nipple (9) that distributes and fills the grease composition into the sealed space from the ball direction change path formed on the end plate (5). To have.

  The grease composition is applied to the linear guide, for example, by loading the grease composition into a grease gun, and from the grease nipple (9) of the linear guide to the left and right shoulders of the track rail (1) and the moving block (2). It is performed by filling in a sealed space formed between the left and right corners.

The grease composition of the present embodiment can also be applied to a linear actuator with a dustproof mechanism described in International Publication No. 2009 / 034804A1 and International Publication No. 2009 / 020075A1. On the other hand, the linear actuator (100) of FIG. 2 has a ball screw and a ball screw nut that engages with the ball screw, and can reciprocate linearly in the axial direction of the ball screw as the ball screw rotates. A moving stage (10), a housing member (11) installed so as to cover at least the ball screw, and openings (12, 13) formed in the housing member along the movement locus of the moving stage And a dustproof belt (14, 15) disposed inside the housing member for sealing the opening, and the opening of the moving stage is maintained while the opening is blocked by the dustproof belt. In order to realize the movement along the section, a detour means for detouring the dustproof belt at a position overlapping with the movement stage is provided. Are those formed by providing a di-, the grease composition of the present embodiment can be encapsulated by using a grease gun or the like to linear motion guide of the linear actuator, a ball screw and a rolling bearing (not shown).
When the grease composition of the present embodiment is applied to a linear actuator in which a suction port is further installed in the linear actuator with a dustproof mechanism described in the pamphlet of International Publication No. 2009 / 020075A1, the same clean as the conventional one The conventional suction amount can be greatly reduced while maintaining the degree.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but these do not limit the present invention.

<Manufacture of grease composition>
Grease compositions were prepared according to the formulations shown in Tables 1-1 and 1-2. The physical properties of each grease composition are also shown in Table 1.

＊表中、ＡＤＥはアルキル置換ジフェニルエーテル油（(株)松村石油研究所製モレスコハイルーブ ＬＢ−１００）を示し、ポリオールエステルはネオペンチルポリオールカルボ
ン酸エステル油を示し、脂肪族系エステルはジペンタエリスリトールカルボン酸エステルを示し、ＰＦＰＥは直鎖型パーフルオロポリエーテルを示し、ＰＴＦＥはポリテトラフルオロエチレンを示し、実施例ではＤｕＰｏｎｔ社製 Ｚｏｎｙｌ ＭＰ１６００Ｎ を使用
している。

* In the table, ADE indicates an alkyl-substituted diphenyl ether oil (Moleco High Lube LB-100 manufactured by Matsumura Oil Research Co., Ltd.), polyol ester indicates neopentyl polyol carboxylic acid ester oil, and aliphatic ester indicates dipenta Erythritol carboxylate ester is shown, PFPE is linear perfluoropolyether, PTFE is polytetrafluoroethylene, and Zonyl MP1600N manufactured by DuPont is used in the examples.

<Experiment 1> (Dust generation measurement 1)
The dust generation test was performed using a dust generation test apparatus in which a linear guide (made by THK) equipped with a ball screw was installed.
A ball screw having a shaft diameter of 25 mm, a lead diameter of 5 mm, and an accuracy of C0 was used. The amount of grease composition enclosed was 6 cc / nut.
Dust generation test apparatus: A downflow type dust generation test apparatus equipped with a particle counter (KC-01D; manufactured by Rion Co., Ltd.) and a recorder (GL-200; manufactured by Graphtec Co., Ltd.) was used as a measuring instrument.
Clean air (temperature 23 ± 1 ° C., cleanliness: JIS class 2) is supplied into the dust generation test apparatus at a rate of 0.3 L / min by a down flow method.
<Operating conditions of dust generation test equipment>
Clean air was allowed to flow into the particle counter at a flow rate of 0.25 mL / s while entraining oil (dust generation) scattered from the ball screw. The operating conditions of the ball screw at this time were a maximum speed of 300 mm / s (3600 min ⁻¹ ), an acceleration of 2.94 m / s ² (0.3 G), and a stroke of 200 mm. The operation pattern was a repetitive operation of driving for 15 seconds and stopping for 180 seconds.
<Measurement conditions of particles>
The sampling time was 75 seconds, the suction amount was 1 L, the stop was repeated for 120 seconds, and the measurement was performed for 24 hours. At this time, a thermocouple was attached to the side surface of the nut, and the calorific value was measured simultaneously.

<Result>
The result regarding the obtained dust generation amount is shown in FIGS. About the result of the emitted-heat amount, it was as showing in Table 1-2.

  The amount of dust generated when Grease 1 is used is extremely small compared to a grease composition using ester oil as a base oil and polyurea or diurea as a thickener, which is conventionally used. Even when compared with a grease composition using fluoropolyether and PTFE as a thickener, it was equivalent or less. This is presumably because the average primary particle size of PTFE is as small as 0.2 μm or less, so that the surface area is large and the oil retention is high, and the PTFE is uniformly dispersed.

<Experiment 2> (Dust generation measurement 2)
The amount of dust generated when the grease composition was sealed in a suction actuator was measured.
A downflow type dust generation test apparatus equipped with a suction actuator was used to measure the amount of dust generation.
The downflow type dust generation test apparatus used was equipped with a particle counter (KC-18; manufactured by Rion Co., Ltd.) and a flow meter (sensor).
The shaft diameter of the ball screw included in the suction actuator was 15 mm, the lead diameter was 30 mm, the amount of grease composition enclosed was 0.9 cm ^3, and the amount of grease composition enclosed in the linear guide was 0.5 cm ³ .
The operation condition of the downflow apparatus was that clean air (temperature 23 ± 1 ° C.) was supplied at 0.3 L / min by the downflow method.
When the actuator was driven, air was sucked from both ends at 40 L / min to reduce the amount of dust generated from the inside of the actuator.
The operating conditions of the actuator are as follows: speed 1.5 m / s (3000 min ⁻¹ ), acceleration 9.8 m / s ² (1 G), stroke 520 mm, stop time 0.5 / s, measurement unit air flow rate 0.25 m / s, Sampling air amount was 1L.
The grease compositions used in this measurement were greases 1, 4 and 7. Measurement of dust generation in continuous operation for 50 hours was carried out every 0.1, 0.15, 0.2, 0.3, 0.5 μm or more of the particle diameter.
The obtained results are shown in FIGS.
As for grease 1, the generation amount of particles having a particle diameter of 0.3 μm or more is extremely small, and class 3 according to the ISO 14644-1 standard has been realized. As for the grease 4, a result that the amount of generated dust was particularly small for the grease having a large particle diameter compared to the grease 7 was obtained.

<Experiment 3> (Measurement of oil film strength)
According to ASTM D5706, the oil film strength (abrasion resistance) of the grease composition was evaluated by a step load test. The ball-on-disk type tester used was an SRV (registered trademark) 4 tribometer made by Optimol.
Experimental conditions:
Ball diameter 10mm (point contact) Material 52100 Steel Test temperature 75 ℃, 125 ℃
Vibration frequency 50Hz Stroke 1mm
Experimental operation: The load was increased by 100 N every 2 minutes, and when the friction coefficient became 0.3 or more, the experiment was stopped because the oil film was broken. The load when the experiment was stopped was recorded as a numerical value representing the oil film strength. The grease composition used in this experiment and the results are as follows.

  As is apparent from the following results, the grease 1 of this embodiment has excellent properties with respect to oil film strength. In particular, there was little decrease in oil film strength against heat changes. In contrast, the fluorine-based greases shown below (both containing PFPE as the base oil and PTFE as the thickener) all stopped the experiment when the load was around 100 N.

(At 75 ° C)
Fomblin (manufactured by Solvay Solexis) <100N
Daikin L-65 (manufactured by Daikin Industries, Ltd.) 100N
Krytox 240AD (DuPont) <100N
NyeTorr 5300 (manufactured by Nye Lubricants) 100N
Grease 1 700N
Grease 8 100N
NyeTorr 5200 (manufactured by Nye Lubricants) 600N

(At 125 ° C)
Grease 1 800N
Grease 8 100N
NyeTorr 5200 (manufactured by Nye Lubricants) 100N

  From the above results, the grease composition of the present invention containing a base oil and a thickener, which contains an ester oil or an ether oil containing no fluorine as the base oil, and the thickener is self-lubricating. In the case of using a grease composition containing a thickener having a property, it is possible to realize a low dust generation performance that exceeds that of commercially available low dust generation grease and fluorine grease. At the same time, wear resistance, which is a weak point of commercially available fluorine grease, is also improved due to its high oil film strength. This is particularly when an alkyl-substituted diphenyl ether oil is used as the base oil, and 40 to 50% by weight of PTFE having a self-lubricating property as a thickener and having an average primary particle size of 0.1 to 0.2 μm or less is added. , Become more prominent. Also, those using alkyl-substituted diphenyl ether oil as the base oil are used for vacuum transportation of solar panel manufacturing equipment, etc. that require medium to low vacuum (Fig. 7: Vapor pressure curve of grease 1), low dust generation, wear resistance, etc. Suitable for lubricating grease for linear motion guide parts used in parts.

Claims (7)

A grease composition containing a base oil and a thickener,
Containing ester oil or fluorine-free ether oil as the base oil,
A grease composition comprising a thickener wherein the thickener has self-lubricating properties. The grease composition of claim 1, wherein the thickener comprises polytetrafluoroethylene. The grease composition according to claim 1 or 2, wherein the content of the thickener is 20 to 60% by weight based on the total amount of the grease composition. The grease composition according to any one of claims 1 to 3, wherein an average primary particle size of the thickener is 0.5 µm or less. The ether oil containing no fluorine as the base oil, and the ether oil containing no fluorine contains an alkyl-substituted diphenyl ether represented by the following formula (1). Grease composition.

(Wherein, ^{R 1} and ^{R 2} is a hydrocarbon group having 10 to 20 carbon atoms, ^{R 1} and ^{R 2} may be of different, even the same. Further, m and n are 1 ≦ m + n ≦ 4 is satisfied, and an integer of 0 or more is shown.) The grease composition according to any one of claims 1 to 4, comprising the ester oil as the base oil, wherein the ester oil contains at least one selected from the following general formula.
(1) a diester synthetic oil represented by R ³ OCO (CH ₂ ) _n COOR ⁴ ;
(Wherein, ^{R 3} and ^{R 4} may be the same or different, represents an aliphatic hydrocarbon group having 3 to 18 carbon atoms, n represents shows 3-12)
(2) a triester synthetic oil represented by C ₂ H ₅ C (CH ₂ OCOR ⁵ ) ₃ ;
(In the formula, three R ^{5 s} may be the same or different and represent an aliphatic hydrocarbon group having 3 to 10 carbon atoms)
(3) a tetraester synthetic oil represented by C (CH ₂ OCOR ⁶ ) ₄ ,
(Wherein, four R ^{6 s} may be the same or different and represent an aliphatic hydrocarbon group having 3 to 10 carbon atoms)
(4) Dipentaerythritol-based synthetic oil represented by C (CH ₂ OCOR ⁷ ) ₃ CH ₂ OCH ₂ C (CH ₂ OCOR ⁷ ) ₃ , and (wherein 6 R ⁷ may be the same or different) Well, an aliphatic hydrocarbon group having 3 to 10 carbon atoms)
(5) Other neopentyl polyol ester synthetic oils.
(The hydrocarbon group of the acyl group represents an aliphatic hydrocarbon group having 3 to 10 carbon atoms) The motion guide apparatus lubricated with the grease composition as described in any one of Claims 1-6.

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