阅读说明：本技术 精密仪器用润滑脂组合物和使用该润滑脂组合物的钟表 (Grease composition for precision instruments and timepiece using the same ) 是由 赤尾祐司 于 2020-08-19 设计创作，主要内容包括：本发明提供一种精密仪器用润滑脂组合物,其能够在钟表的滑移机构上形成牢固的润滑被膜,防止滑移机构的劣化和转矩的降低的能力的持续性优异。上述精密仪器用润滑脂组合物包含基础油、增稠剂和耐磨损剂,上述基础油是碳原子数为30以上的石蜡系烃油(A－1)等,上述增稠剂为锂皂或双脲化合物,上述耐磨损剂为下述通式(b－1)表示的中性磷酸酯(B－1)等,上述耐磨损剂在上述精密仪器用润滑脂组合物100质量％中以0.1质量％～20质量％的量含有。(The invention provides a grease composition for precision instruments, which can form firm lubrication on a sliding mechanism of a clockThe sliding film is excellent in the durability of the capability of preventing deterioration of the sliding mechanism and reduction of torque. The grease composition for precision instruments comprises a base oil, a thickener and an abrasion resistant agent, wherein the base oil is paraffin hydrocarbon oil (A-1) having 30 or more carbon atoms, the thickener is a lithium soap or a diurea compound, the abrasion resistant agent is a neutral phosphate ester (B-1) represented by the following general formula (B-1), and the abrasion resistant agent is contained in an amount of 0.1 to 20 mass% in 100 mass% of the grease composition for precision instruments.)

1. A grease composition for precision instruments, comprising a base oil, a thickener and a wear resistant agent,

the base oil is at least 1 selected from paraffin hydrocarbon oil (A-1) with carbon number more than 30, polyalcohol ester oil (A-2) and ether oil (A-3),

the thickener is a lithium soap or a diurea compound,

the abrasion resistant agent is at least 1 selected from the group consisting of a neutral phosphate (B-1) represented by the following general formula (B-1) and a neutral phosphite (B-2) represented by the following general formula (B-2),

the wear-resistant agent is contained in an amount of 0.1 to 20% by mass based on 100% by mass of the grease composition for precision instruments,

in the formula (b-1), R^b11～R^b14Each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms, R^b15～R^b18Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms, R^b191And R^b192Each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, R^b191And R^b192The total number of carbon atoms of (a) is 1 to 5,

in the formula (b-2), R^b21～R^b24Each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms, R^b25～R^b28Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms, R^b291And R^b292Each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, R^b291And R^b292The total number of carbon atoms of (a) is 1 to 5.

2. The grease composition for precision instruments according to claim 1, further comprising polytetrafluoroethylene as a solid lubricant.

3. The grease composition for precision instruments according to claim 1 or 2, further comprising at least 1 selected from diphenylamine derivatives (C-1) represented by the following general formula (C-1) and hindered amine compounds (C-2) represented by the following general formula (C-2) as an antioxidant,

in the formula (c-1), R^c11And R^c12Each independently represents a carbon atomA linear or branched alkyl group having a sub-number of 1 to 10, p and q each independently represent an integer of 0 to 5, wherein p and q do not represent 0 at the same time,

in the formula (c-2), R^c21And R^c22Each independently represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms, R^c23Represents a 2-valent aliphatic hydrocarbon group having 1 to 10 carbon atoms.

4. The grease composition for precision instruments according to any one of claims 1 to 3, wherein the thickener is a lithium soap.

5. The grease composition for precision instruments according to any one of claims 1 to 4, wherein the mixing consistency measured according to JIS K22207 is 400 to 450.

6. The grease composition for precision instruments according to any one of claims 1 to 4, wherein the viscosity at 25 ℃ is 1000 to 3000 mPas.

7. A timepiece having a sliding part to which the grease composition for precision instruments according to any one of claims 1 to 6 is attached.

Technical Field

The present invention relates to a grease composition for precision instruments and a timepiece using the same.

Background

Patent document 1 describes a grease composition for precision instruments, which contains a lithium soap grease or a urea grease and an anti-wear agent. Specific examples of the abrasion resistant agent include neutral phosphates such as triolein phosphate, neutral phosphites such as triolein phosphite, and calcium borate. The grease composition for precision instruments is used by adhering to a sliding mechanism of a timepiece and forming a lubricating film.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2004/018594

Disclosure of Invention

However, the grease composition for precision instruments of patent document 1 has a weak lubricating film, and thus has room for improvement in the durability of the capability of preventing deterioration of the sliding mechanism and reduction of torque.

Accordingly, an object of the present invention is to provide a grease composition for precision instruments, which can form a strong lubricating film on a sliding mechanism of a timepiece, and has excellent durability of ability to prevent deterioration of the sliding mechanism and torque reduction.

The grease composition for precision instruments comprises a base oil, a thickener and an abrasion resistant agent, wherein the base oil is at least 1 selected from paraffin hydrocarbon oil (A-1) having 30 or more carbon atoms, polyol ester oil (A-2) and ether oil (A-3), the thickener is a lithium soap or a diurea compound, the abrasion resistant agent is at least 1 selected from neutral phosphate (B-1) represented by the following general formula (B-1) and neutral phosphite (B-2) represented by the following general formula (B-2), and the abrasion resistant agent is contained in an amount of 0.1 to 20 mass% in 100 mass% of the grease composition for precision instruments.

(in the formula (b-1), R^b11～R^b14Each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms, R^b15～R^b18Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms, R^b191And R^b192Each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, R^b191And R^b192The total number of carbon atoms of (a) is 1 to 5. )

(in the formula (b-2), R^b21～R^b24Each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms, R^b25～R^b28Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms, R^b291And R^b292Each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, R^b291And R^b292The total number of carbon atoms of (a) is 1 to 5. )

The grease composition for precision instruments of the present invention can form a strong lubricating film on the sliding mechanism of a timepiece, and has excellent durability of the ability to prevent deterioration of the sliding mechanism and reduction of torque.

Detailed Description

The embodiment (embodiment) for carrying out the present invention will be described in detail. The present invention is not limited to the contents described in the following embodiments. The constituent elements described below include elements that can be easily assumed by those skilled in the art, and substantially the same elements. The following configurations may be combined as appropriate. Various omissions, substitutions, and changes in the configuration may be made without departing from the scope of the present invention.

< lubricating grease composition for precision instruments >

The grease composition for precision instruments of an embodiment includes a base oil, a thickener, and an anti-wear agent.

[ base oil ]

The base oil is at least 1 selected from a paraffin hydrocarbon oil (A-1) having 30 or more carbon atoms, a polyol ester oil (A-2) and an ether oil (A-3).

The paraffin hydrocarbon oil (A-1) is preferably an alpha-olefin polymer having 30 or more carbon atoms, preferably 30 to 50 carbon atoms. The paraffin-based hydrocarbon oil (A-1) may be used alone in 1 kind, or may be used in combination with 2 or more kinds. Examples of the α -olefin polymer include homopolymers of 1 monomer selected from ethylene and an α -olefin having 3 to 18 carbon atoms, preferably an α -olefin having 10 to 18 carbon atoms, and copolymers of at least 2 or more monomers selected from ethylene and an α -olefin having 3 to 18 carbon atoms, preferably an α -olefin having 10 to 18 carbon atoms. Specific examples thereof include a trimer of 1-decene, a trimer of 1-undecene, a trimer of 1-dodecene, a trimer of 1-tridecene, a trimer of 1-tetradecene, and a copolymer of 1-hexene and 1-pentene. The paraffin-based hydrocarbon oil (A-1) preferably has a kinematic viscosity of 4cSt to 6cSt at 100 ℃.

The polyol ester oil (a-2) is preferably a polyol ester oil having no hydroxyl group in the molecule from the viewpoint of preventing corrosion of timepiece parts. The polyol ester oil (A-2) may be used alone in 1 kind or in combination of 2 or more kinds.

Such a polyol ester oil can be produced by reacting a polyol having at least 2 hydroxyl groups in 1 molecule with a monobasic acid or a salt thereof in a mixing molar ratio ((monobasic acid or salt thereof)/polyol) of 1 or more. In this case, the obtained polyol ester oil (A-2) was a complete ester having no hydroxyl group in the molecule.

Examples of the polyhydric alcohol include neopentyl glycol, trimethylolpropane, pentaerythritol, and dipentaerythritol.

Examples of the monobasic acid include saturated aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, pivalic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, and palmitic acid;

unsaturated aliphatic monocarboxylic acids such as stearic acid, acrylic acid, crotonic acid, and oleic acid;

cyclic carboxylic acids such as benzoic acid, methylbenzoic acid, naphthoic acid, cinnamic acid, cyclohexanecarboxylic acid, nicotinic acid, isonicotinic acid, furan-2-carboxylic acid, pyrrole-N-carboxylic acid, monoethyl malonate and monoethyl phthalate, and the like.

Examples of the salt of the monobasic acid include a chloride of the monobasic acid.

Specific examples of the polyol ester oil (A-2) include a mixed ester of neopentyl glycol-capric acid/caprylic acid, a mixed ester of trimethylolpropane-valeric acid/heptanoic acid, a mixed ester of trimethylolpropane-capric acid/caprylic acid, trimethylolpropane nonanoate, and a mixed ester of pentaerythritol-heptanoic acid/decanoic acid.

From the viewpoint of preventing corrosion of timepiece parts, the ether oil (a-3) is preferably an ether oil having no hydroxyl group in the molecule, and more preferably an ether oil represented by the following formula (1). The ether oil (A-3) may be used alone in 1 kind, or may be used in combination with 2 or more kinds.

In the formula (1), R¹And R³Each independently represents an alkyl group having 1 to 18 carbon atoms or a 1-valent aromatic hydrocarbon group having 6 to 18 carbon atoms. R²Represents an alkylene group having 1 to 18 carbon atoms or a 2-valent aromatic hydrocarbon group having 6 to 18 carbon atoms. n is an integer of 1 to 5.

Specific examples of the alkyl group having 1 to 18 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl. Specific examples of the 1-valent aromatic hydrocarbon group having 6 to 18 carbon atoms include a phenyl group, a tolyl group, a xylyl group, a benzyl group, a phenethyl group, a 1-phenylethyl group, a 1-methyl-1-phenylethyl group and the like.

Specific examples of the alkylene group having 1 to 18 carbon atoms include a methylene group, an ethylene group, a propylene group, and a butylene group. Specific examples of the 2-valent aromatic hydrocarbon group having 6 to 18 carbon atoms include a phenylene group and a 1, 2-naphthylene group.

[ thickener ]

The thickener is a lithium soap or a diurea compound.

Examples of the lithium soap include lithium stearate soap and 12-hydroxystearic acid lithium soap, and it is preferable to use 12-hydroxystearic acid lithium soap.

The diurea compound is preferably a diurea compound represented by the following formula (2).

R⁴-HNCONH-R⁵-HNCONH-R⁶ (2)

In the formula (2), R⁴And R⁶Each independently represents a C1-10 hydrocarbon group, R⁵Represents a hydrocarbon group having 6 to 15 carbon atoms.

As R⁴And R⁶Specifically, the alkyl group has 1 to 10 carbon atoms. Among them, butyl, pentyl, hexyl and heptyl are preferable. As R⁵Specific examples thereof include groups represented by the following formulas (2-1) to (2-3). Among them, preferred are groups represented by the following formulae (2-1) and (2-2).

The grease composition for precision instruments obtained using a lithium soap as a thickener can exhibit the ability to prevent deterioration of the sliding mechanism and reduction of torque even at low temperatures.

[ abrasion resistant agent ]

The anti-abrasion agent is at least one selected from the group consisting of neutral phosphate esters (B-1) and neutral phosphite esters (B-2). As the abrasion resistant agent, 1 kind of neutral phosphate (B-1) may be used, or 2 or more kinds of neutral phosphate (B-1) may be used in combination. The same applies to the neutral phosphite (B-2). Further, neutral phosphate (B-1) and neutral phosphite (B-2) may be used in combination of 1 or 2 or more. The neutral phosphate ester (B-1) is represented by the following general formula (B-1), and the neutral phosphite ester (B-2) is represented by the following general formula (B-2).

Neutral phosphorusThe acid ester (B-1) has a 2-benzene ring structure in the central part. It is considered that when the grease composition for precision instruments is attached to the sliding part, a wide range of the surface of the sliding part can be covered by these benzene ring structures. As described later, the neutral phosphate ester (B-1) is present in R^b11～R^b14Having 4 specific aliphatic hydrocarbon groups. It is considered that when the grease composition for precision instruments is adhered to the sliding part, the grease composition can be firmly adhered to the sliding part by the specific aliphatic hydrocarbon group, and the whole neutral phosphate (B-1) is unlikely to be peeled off. The same holds true for the neutral phosphite (B-2). Therefore, when the grease composition for precision instruments using such an abrasion resistant agent is adhered to a sliding part, a strong lubricating film can be formed. Therefore, the wear resistance and extreme pressure property can be improved. That is, the durability of the ability to prevent deterioration of the slipping mechanism and reduction of torque is excellent.

In the formula (b-1), R^b11～R^b14Each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms.

The aliphatic hydrocarbon group having 10 to 16 carbon atoms may be a linear, branched or cyclic aliphatic hydrocarbon group, or may be a saturated or unsaturated aliphatic hydrocarbon group. Specific examples of the aliphatic hydrocarbon group having 10 to 16 carbon atoms include linear alkyl groups such as decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and hexadecyl (cetyl).

R^b15～R^b18Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms.

Examples of the linear or branched alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a n-pentyl group, a n-hexyl group, an isopropyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a tert-pentyl group, a neopentyl group, and an isohexyl group.

Neutral phosphate ester (B-1) due to its presence in R^b15～R^b18Having a specific substituent onTherefore, even when the grease composition for a precision instrument is used for a sliding portion to which a large pressure is applied during sliding, the wear resistance and extreme pressure property can be improved. This is believed to be due to the presence of a metal ion at R^b15～R^b18When the above groups have a specific substituent, the film of the grease composition for precision instruments adhered to the sliding part becomes stronger.

In particular, R^b15And R^b17Is a linear alkyl group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, R^b16And R^b18The effect of improving the abrasion resistance and extreme pressure properties is further enhanced when the alkyl group is a branched alkyl group having 3 to 6 carbon atoms, preferably 3 to 4 carbon atoms.

R^b191And R^b192Each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms.

Examples of the linear or branched alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an isopropyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a tert-pentyl group, and a neopentyl group.

However, R^b191And R^b192The total number of carbon atoms of (a) is 1 to 5. Thus, for example, R^b191When it is a hydrogen atom, R^b192Is a linear or branched alkyl group having 1 to 5 carbon atoms, R^b191When it is methyl, R^b192Is a linear or branched alkyl group having 1 to 4 carbon atoms, R^b191When it is ethyl, R^b192Is a linear or branched alkyl group having 2 to 3 carbon atoms.

In particular, R is more preferable for making the film of the grease composition for precision instruments stronger^b191Is a hydrogen atom, R^b192Is a linear or branched alkyl group having 1 to 5 carbon atoms.

In the formula (b-2), R^b21～R^b24Each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms.

The aliphatic hydrocarbon group having 10 to 16 carbon atoms may be a linear, branched or cyclic aliphatic hydrocarbon group, or may be a saturated or unsaturated aliphatic hydrocarbon group. Specific examples of the aliphatic hydrocarbon group having 10 to 16 carbon atoms include linear alkyl groups such as decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and hexadecyl (cetyl).

R^b25～R^b28Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms.

Examples of the linear or branched alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a n-pentyl group, a n-hexyl group, an isopropyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a tert-pentyl group, a neopentyl group, and an isohexyl group.

Neutral phosphite (B-2) due to its presence in R^b25～R^b28Since the grease composition for a precision instrument has a specific substituent, even when the grease composition for a precision instrument is used for a sliding portion to which a large pressure is applied during sliding, the wear resistance and extreme pressure properties can be improved. This is believed to be due to the presence of a metal ion at R^b25～R^b28When the above groups have a specific substituent, the film of the grease composition for precision instruments adhered to the sliding part becomes stronger.

In particular R^b25And R^b27Is a linear alkyl group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms and R^b26And R^b28The effect of improving the abrasion resistance and extreme pressure properties is further improved when the branched alkyl group has 3 to 6 carbon atoms, preferably 3 to 4 carbon atoms.

R^b291And R^b292Each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms.

Examples of the linear or branched alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an isopropyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a tert-pentyl group, and a neopentyl group.

Wherein R is^b291And R^b292The total number of carbon atoms of (a) is 1 to 5. Thus, for example, R^b291When it is a hydrogen atom, R^b292Is a linear or branched alkyl group having 1 to 5 carbon atoms, R^b291When it is methyl, R^b292Is a linear or branched alkyl group having 1 to 4 carbon atoms, R^b291When it is ethyl, R^b292Is a linear or branched alkyl group having 2 to 3 carbon atoms.

In particular, R is more preferable for making the film of the grease composition for precision instruments stronger^b291Is a hydrogen atom, R^b292Is a linear or branched alkyl group having 1 to 5 carbon atoms.

Since the grease composition for precision instruments is considered to have higher structural stability, it is more preferable to use the neutral phosphite (B-2).

[ solid Lubricant ]

In order to prevent frictional wear of the sliding portion, the grease composition for a precision instrument according to the embodiment may further contain Polytetrafluoroethylene (PTFE) as a solid lubricant. The PTFE may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Usually, PTFE is in the form of particles, and the 1 st-order particle diameter is preferably in the range of 0.5 to 8 μm. Since PTFE is white, when PTFE is used, the grease composition for precision instruments can have a good appearance. On the other hand, when molybdenum disulfide is used as the solid lubricant, the grease composition for precision instruments is inferior in appearance. This is because the color of molybdenum disulfide causes the color of the grease composition for precision instruments to be the color of the wear powder mixed in from before use.

[ antioxidant ]

The grease composition for precision instruments according to the embodiment may further contain an antioxidant in order to suppress the formation of deposits such as wear powder and rust on sliding portions. The antioxidant is at least 1 selected from diphenylamine derivatives (C-1) and hindered amine compounds (C-2). As the antioxidant, 1 type of diphenylamine derivative (C-1) may be used, or 2 or more types of diphenylamine derivatives (C-1) may be used in combination. The same applies to the hindered amine compound (C-2). Further, the diphenylamine derivative (C-1) and the hindered amine compound (C-2) may be used in 1 type or 2 or more types in combination. The diphenylamine derivative (C-1) is represented by the following general formula (C-1), and the hindered amine compound (C-2) is represented by the following general formula (C-2).

When the diphenylamine derivative (C-1) and the hindered amine compound (C-2) are combined, the formation of precipitates such as wear debris and rust can be further suppressed even when the grease composition for precision instruments is used in a sliding portion to which a large pressure is applied during sliding. Further, discoloration of the sliding portion is less likely to occur, and durability can be improved. This is considered to be because, when the diphenylamine derivative (C-1) and the hindered amine compound (C-2) are combined, even active species generated in a sliding portion to which a large pressure is applied during sliding can be made harmless for a long period of time.

In the formula (c-1), R^c11And R^c12Each independently represents a linear or branched alkyl group having 1 to 10 carbon atoms.

Examples of the linear or branched alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an isopropyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a tert-pentyl group, a neopentyl group, an isohexyl group, a 2-ethylhexyl group, a 2,4, 4-trimethylpentyl group, a 1,1,3, 3-tetramethylbutyl group.

p and q each independently represent an integer of 0 to 5, preferably 0 to 3. However, p and q do not simultaneously represent 0.

The diphenylamine derivative is obtained, for example, by reacting diphenylamine with a compound (e.g., a compound having a double bond such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 2-butene, 2-methylpropene, 3-methyl-1-butene, 2-methyl-1-butene, 4-methyl-1-pentene, 2-ethyl-1-hexene, or 2,4, 4-trimethylpentene) having a linear or branched alkyl group having 1 to 10 carbon atoms as a substituent.

In the formula (c-2), R^c21And R^c22Each independently represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms.

The aliphatic hydrocarbon group having 1 to 10 carbon atoms may be a linear, branched or cyclic aliphatic hydrocarbon group, or may be a saturated or unsaturated aliphatic hydrocarbon group.

Specific examples of the aliphatic hydrocarbon group having 1 to 10 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, heptyl, octyl, nonyl, decyl, isopropyl, sec-butyl, isobutyl, tert-butyl, isopentyl, tert-pentyl, neopentyl, isohexyl, and 2-ethylhexyl. Among them, from the viewpoint of improving durability, a linear or branched alkyl group having 5 to 10 carbon atoms is more preferable.

R^c23Represents a 2-valent aliphatic hydrocarbon group having 1 to 10 carbon atoms.

As the aliphatic hydrocarbon group having a valence of 2 and having 1 to 10 carbon atoms, a linear or branched alkylene group having a valence of 2 such as a methylene group, a 1, 2-ethylene group, a 1, 3-propylene group, a 1, 4-butylene group, a 1, 5-pentylene group, a 1, 6-hexylene group, a 1, 7-heptylene group, a 1, 8-octylene group, a 1, 9-nonylene group, a 1, 10-decylene group, or a 3-methyl-1, 5-pentylene group is preferably used. Among them, from the viewpoint of improving durability, a 2-valent linear or branched alkylene group having 5 to 10 carbon atoms is more preferable.

In particular, from the viewpoint of improving durability at high temperatures, R in the above group is more preferable^c21、R^c22And R^c23The sum of the number of carbon atoms of (a) is 16 to 30.

[ Metal deactivator ]

The grease composition for precision instruments according to the embodiment may further contain a metal deactivator. The metal passivator may be used alone in 1 kind, or in combination of 2 or more kinds. As the metal deactivator, benzotriazole or a derivative thereof is preferable.

Specific examples of the benzotriazole derivative include compounds represented by the following formula (3) such as 2- (2 '-hydroxy-5' -methylphenyl) benzotriazole, 2- [2 '-hydroxy-3', 5 '-bis (. alpha.,. alpha. -dimethylbenzyl) phenyl ] benzotriazole, 2- (2' -hydroxy-3 ', 5' -di-t-butylphenyl) benzotriazole, 1- (N, N-bis (2-ethylhexyl) aminomethyl) benzotriazole, and compounds represented by the following formula (4).

In the formula (3), R⁷、R⁸And R⁹Each independently represents an alkyl group having 1 to 18 carbon atoms. In the formula (4), R¹⁰Represents an alkyl group having 1 to 18 carbon atoms.

In the grease composition for precision instruments of the embodiment, the wear-resistant agent is contained in an amount of 0.1 to 20 mass% in 100 mass% of the grease composition for precision instruments. When the wear-resistant agent is contained in the above amount, a strong lubricating film can be formed. Therefore, the wear resistance and extreme pressure property can be improved. That is, the durability of the ability to prevent deterioration of the slipping mechanism and reduction of torque can be improved. When a solid lubricant is used, the solid lubricant is preferably contained in an amount of 0.01 to 15% by mass based on 100% by mass of the grease composition for precision instruments. When an antioxidant is used, the antioxidant is preferably contained in an amount of 0.01 to 3% by mass based on 100% by mass of the grease composition for precision instruments. When the metal deactivator is used, the metal deactivator is preferably contained in an amount of 0.01 to 3% by mass based on 100% by mass of the grease composition for precision instruments. In the grease composition for precision instruments according to the embodiment, the remaining part is usually a base oil and a thickener.

The grease composition for precision instruments of the embodiments may be solid or semi-solid, and may be paste-like or liquid. The state of the grease composition for precision instruments can be adjusted by changing the amounts of the base oil and the thickener. In the case of a solid or semisolid, the thickener is contained in an amount of, for example, 8.5 to 25.0 parts by mass per 100 parts by mass of the base oil. In the case of a paste, for example, the thickener is contained in an amount of more than 2.7 parts by mass and less than 8.5 parts by mass, preferably 3.0 parts by mass to 8.0 parts by mass, based on 100 parts by mass of the base oil. In the case of a liquid, the thickener is contained in an amount of, for example, 0.25 to 2.7 parts by mass per 100 parts by mass of the base oil.

When the grease composition for precision instruments is solid or semisolid, the mixing consistency measured according to JIS K22207 is preferably 20 to 45. Further, when the grease composition for precision instruments is in the form of a paste, the mixing consistency measured according to JIS K22207 is preferably 400 to 450.

When the grease composition for precision instruments is in a liquid state, the viscosity at 25 ℃ is preferably 1000 mPas to 3000 mPas. The viscosity can be measured by using an E-type viscometer at 25 ℃. In the present specification, the grease composition for precision instruments is also referred to as a paste or liquid state, in addition to a solid or semisolid state.

The grease composition for precision instruments according to the embodiment contains the wear-resistant agent having the above-described structure. In the sliding portion, it is considered that the abrasion resistant agent covers the surface of the sliding portion widely in the lattice structure of the thickener, and can maintain a state of being less likely to be peeled off. Therefore, when the grease composition for precision instruments according to the embodiment is used for a sliding mechanism of a timepiece, the durability of the ability to prevent deterioration of the sliding mechanism and reduction of torque can be improved.

In addition, when the grease composition for precision instruments according to the embodiment is in a paste or liquid state (particularly, in a liquid state), the durability of the above-described capability can be further improved. This is considered to be because the composition, even if temporarily moved from the position where it was attached, is more likely to return to the original position again when sliding than in the case of a solid or semi-solid.

In the case of a mesh structure in which no thickener is present, for example, in the case of a lubricating oil composition containing a base oil and an anti-wear agent, even if the anti-wear agent has the above structure, the composition may move too freely when used in a sliding portion to which a large pressure is applied during sliding. Therefore, it is considered that the abrasion resistant agent may be peeled off from the surface of the sliding portion.

Further, when the grease composition for precision instruments is in the form of paste or liquid (particularly, in the form of liquid), the durability of the above-mentioned capability can be improved even at low temperatures (for example, -50 ℃).

Further, when the grease composition for precision instruments is in the form of paste or liquid, it is easy to adhere to sliding parts and easy to handle.

When the grease composition for precision instruments according to the embodiment is applied to a clock slip mechanism, the reduction rate (torque reduction rate) of the slip torque after a 12-year acceleration test at normal temperature (e.g., 25 ℃) can be 10% or less. In the present specification, the torque reduction rate is a rate of change of the slip torque after the 12-year acceleration test of the timepiece alignment with respect to the slip torque at the start of the running test of the slipping mechanism. In particular, when a lithium soap is used as the thickener, the torque reduction rate can be 10% or less even at a low temperature (for example, -50 ℃).

When the grease composition for precision instruments of the embodiment is held at 90 ℃ for 1000 hours, the rate of change in weight (evaporation rate) of the grease composition for precision instruments before and after holding is, for example, 7% by weight or less, preferably 3% by weight or less, more preferably 0.7% by weight or less, and particularly preferably 0.3% by weight or less. When the evaporation rate is within the above range, the timepiece using the grease composition for precision instruments of the embodiment has excellent running stability at high temperatures. Further, it is considered that the evaporation rate can be made within the above range by using the abrasion resistant agent having the above structure.

The grease composition for precision instruments according to the embodiment has a total acid value of, for example, 0.2mgKOH/g or less. When the total acid value is within the above range, corrosion of the timepiece parts can be prevented. Therefore, when applied to a sliding mechanism of a timepiece, the durability of the ability to prevent deterioration of the sliding mechanism and reduction of torque can be further improved.

The grease composition for precision instruments according to the embodiment can be produced by a known method. Generally, first, a base grease comprising a base oil and a thickener is made. The base grease contains, for example, a base oil in an amount of 80 to 90% by mass and a thickener in an amount of 10 to 20% by mass based on 100% by mass of the base grease.

Next, the base grease was further added with a base oil and mixed so that the finally obtained grease composition for precision instruments became a desired state in a solid, semisolid, paste, or liquid state, to obtain a grease. Specifically, when the base oil is solid, semi-solid, or pasty, it is preferably added so that the mixing consistency falls within the above range. In addition, in the case of a liquid, it is preferable to add the base oil so that the viscosity at 25 ℃ falls within the above range. Accordingly, the base oil and the thickener can be blended in the grease composition for precision instruments, which is finally obtained, in the above-mentioned ranges.

In this way, a grease composition for precision instruments can be produced by adding a base oil to the base grease to obtain a grease, and then adding and mixing an abrasion resistant agent and the like.

Since the grease composition for precision instruments according to the embodiment is produced as described above, it may be referred to as a grease composition for precision instruments including a lithium soap grease, an anti-wear agent, and the like, or a grease composition for precision instruments including a urea grease, an anti-wear agent, and the like. Here, the lithium soap grease refers to a grease in which a base oil is further added to a base grease, and the thickener is a lithium soap. The urea grease is a grease in which a base oil is further added to a base grease, and the thickener is a diurea compound.

Clock & watch & lt

In a timepiece according to an embodiment, the grease composition for a precision instrument is attached to a sliding portion (sliding portion) of a center wheel having a sliding mechanism. The timepiece suppresses wear friction of the parts of the sliding mechanism over a long period of time and exhibits stable operability. In addition, the timepiece according to the embodiment may be one in which the grease composition for a precision instrument is attached to another sliding portion (for example, a train portion) of the timepiece. In particular, when the grease composition for precision instruments is in the form of paste or liquid, it is likely to remain at the position where it adheres, and therefore it is also preferably used for wheel train parts.

In the timepiece of the embodiment, it is also conceivable that the grease composition for precision instruments of the embodiment is used for the sliding portion, and the lubricating oil composition for timepieces is used for sliding portions other than the sliding portion. In this case, it is preferable that the kind of the base oil used in the grease composition is the same as the kind of the base oil of the lubricating oil composition. Specifically, the following combinations (1) to (3) are preferable.

(1) Grease composition: a grease composition obtained from a paraffin hydrocarbon oil (A-1).

Lubricating oil composition: a lubricating oil composition obtained from a paraffinic hydrocarbon oil.

(2) Grease composition: a grease composition obtained from the polyol ester oil (A-2).

Lubricating oil composition: a lubricating oil composition derived from a polyol ester oil.

(3) Grease composition: a grease composition obtained from the ether oil (A-3).

Lubricating oil composition: lubricating oil compositions derived from ether oils.

According to such a combination, when both are mixed, the grease composition and the lubricating oil composition are not easily deteriorated, and thus the timepiece can be operated more stably and continuously. In addition, from the viewpoint of stability of operation, the lubricating oil composition preferably contains the anti-wear agent and the antioxidant.

The above description has been given of the case where the grease composition for precision instruments is used for timepieces, but the grease composition for precision instruments may be used for other precision instruments. In particular, a slide mechanism for other precision instruments is preferable.

In summary, the present invention relates to the following.

[1] A grease composition for precision instruments, comprising a base oil, a thickener and an abrasion resistant agent, wherein the base oil is at least 1 selected from paraffin hydrocarbon oil (A-1) having 30 or more carbon atoms, polyol ester oil (A-2) and ether oil (A-3), the thickener is a lithium soap or a diurea compound, the abrasion resistant agent is at least 1 selected from neutral phosphate (B-1) represented by the following general formula (B-1) and neutral phosphite (B-2) represented by the following general formula (B-2), and the abrasion resistant agent is contained in an amount of 0.1 to 20 mass% in 100 mass% of the grease composition for precision instruments.

(in the formula (b-1), R^b11～R^b14Each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms, R^b15～R^b18Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms, R^b191And R^b192Each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, R^b191And R^b192The total number of carbon atoms of (a) is 1 to 5. )

(in the formula (b-2), R^b21～R^b24Each independently represents an aliphatic hydrocarbon group having 10 to 16 carbon atoms, R^b25～R^b28Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms, R^b291And R^b292Each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, R^b291And R^b292The total number of carbon atoms of (a) is 1 to 5. )

[2] The grease composition for precision instruments according to [1], which contains polytetrafluoroethylene as a solid lubricant.

[3] The grease composition for precision instruments according to [1] or [2], which further comprises at least 1 selected from diphenylamine derivatives (C-1) represented by the following general formula (C-1) and hindered amine compounds (C-2) represented by the following general formula (C-2) as an antioxidant.

(in the formula (c-1), R^c11And R^c12Each independently represents a linear or branched alkyl group having 1 to 10 carbon atoms, and p and q each independently represents an integer of 0 to 5. However, p and q do not simultaneously represent 0. )

(in the formula (c-2), R^c21And R^c22Each independently represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms, R^c23Represents a 2-valent aliphatic hydrocarbon group having 1 to 10 carbon atoms. )

The grease composition for precision instruments of the above [1] to [3] can form a strong lubricating film on the glide mechanism of a timepiece, and is excellent in the durability of the ability to prevent degradation of the glide mechanism and torque reduction.

[4] The grease composition for precision instruments according to any one of [1] to [3], wherein the thickener is a lithium soap.

The grease composition for precision instruments obtained using a lithium soap as a thickener can exhibit the ability to prevent deterioration of the sliding mechanism and reduction of torque even at low temperatures.

[5] The grease composition for precision instruments according to any one of [1] to [4], wherein the mixing consistency measured according to JIS K22207 is 400 to 450.

[6] The grease composition for precision instruments according to any one of [1] to [4], wherein the viscosity at 25 ℃ is 1000 to 3000 mPas.

When the grease composition for precision instruments of the above [5] and [6] is applied to a sliding mechanism of a timepiece, the durability of the capability of preventing deterioration of the sliding mechanism and reduction of torque can be further improved.

[7] A watch, wherein the grease composition for precision instruments according to any one of [1] to [6] is adhered to a sliding part.

The timepiece suppresses wear friction of the parts of the sliding mechanism over a long period of time and exhibits stable operability.

The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[ examples ]

[ example 1-1 ]

A base grease was prepared which contained an alpha-olefin polymer having 30 to 50 carbon atoms (kinematic viscosity at 100 ℃ C. of 6cSt) (85 mass%) as a paraffin-based hydrocarbon oil (A-1) and a 12-hydroxystearic acid lithium soap (15 mass%). Subsequently, a trimer of 1-decene (kinematic viscosity at 100 ℃ C. of 5cSt) was further added to the base grease, and mixed to obtain a lithium soap grease. Here, the base grease was used in an amount of 10 parts by mass relative to 90 parts by mass of the trimer of 1-decene added.

To this lithium soap grease, 4' -butylidenebis (3-methyl-6-tert-butylphenyl) -ditridecyl phosphite as a neutral phosphite (B-2), PTFE particles (having a primary particle size of 0.5 to 8 μm) as a solid lubricant, a diphenylamine derivative (trade name Irganox L57, manufactured by Ciba Specialty Chemicals) as an antioxidant (C), and bis (2,2,6, 6-tetramethyl-1- (octyloxy) piperidin-4-yl) sebacate were added to obtain a grease composition for precision instruments. Here, these components were added to 100 mass% of the grease composition for precision instruments so as to contain 5 mass% of neutral phosphite (B-2), 10 mass% of solid lubricant, 0.5 mass% of diphenylamine derivative, and 0.5 mass% of bis (2,2,6, 6-tetramethyl-1- (octyloxy) piperidin-4-yl) sebacate.

The grease composition for precision instruments had a viscosity of 1500 mPas at 25 ℃ and was in a liquid state.

[ examples 1-2 ]

A base grease was prepared which contained an alpha-olefin polymer having 30 to 50 carbon atoms (kinematic viscosity at 100 ℃ C. of 6cSt) (85 mass%) as a paraffin-based hydrocarbon oil (A-1) and a 12-hydroxystearic acid lithium soap (15 mass%). Subsequently, a trimer of 1-decene (kinematic viscosity at 100 ℃ C. of 5cSt) was further added to the base grease, and mixed to obtain a lithium soap grease. Here, the base grease was used in an amount of 15 parts by mass relative to 85 parts by mass of the trimer of 1-decene added.

A grease composition for a precision instrument was obtained in the same manner as in example 1-1, except that the lithium soap grease thus obtained was used.

The grease composition for precision instruments had a viscosity of 2300 mPas at 25 ℃ and was in a liquid state.

[ examples 1 to 3]

A base grease was prepared which contained an alpha-olefin polymer having 30 to 50 carbon atoms (kinematic viscosity at 100 ℃ C. of 6cSt) (85 mass%) as a paraffin-based hydrocarbon oil (A-1) and a 12-hydroxystearic acid lithium soap (15 mass%). Subsequently, a trimer of 1-decene (kinematic viscosity at 100 ℃ C. of 5cSt) was further added to the base grease, and mixed to obtain a lithium soap grease. Here, the base grease was used in an amount of 20 parts by mass relative to 80 parts by mass of the trimer of 1-decene added.

A grease composition for a precision instrument was obtained in the same manner as in example 1-1, except that the lithium soap grease thus obtained was used.

The grease composition for precision instruments had a mixing consistency of 440 measured according to JIS K22207, and was pasty.

[ examples 1 to 4]

A base grease was prepared which contained an alpha-olefin polymer having 30 to 50 carbon atoms (kinematic viscosity at 100 ℃ C. of 6cSt) (85 mass%) as a paraffin-based hydrocarbon oil (A-1) and a 12-hydroxystearic acid lithium soap (15 mass%). Subsequently, a trimer of 1-decene (kinematic viscosity at 100 ℃ C. of 5cSt) was further added to the base grease, and mixed to obtain a lithium soap grease. Here, the base grease was used in an amount of 165 parts by mass relative to 30 parts by mass of the trimer of 1-decene added.

A grease composition for a precision instrument was obtained in the same manner as in example 1-1, except that such a lithium soap grease was used.

The grease composition for precision instruments had a mixing consistency of 27.9 as measured in accordance with JIS K22207, and was in the form of a semisolid.

[ examples 1 to 5]

Instead of the paraffin-based hydrocarbon oil (A-1), a mixed ester of neopentylglycol octanoic acid decanoic acid as the polyol ester (A-2) was used. A base grease containing a mixed ester of neopentyl glycol caprylic acid capric acid (85 mass%) and 12-lithium hydroxystearate soap (15 mass%) was prepared. Next, a neopentyl glycol caprylic/capric acid mixed ester was further added to the base grease and mixed to obtain a lithium soap grease. Here, the above base grease was used in an amount of 10 parts by mass relative to 90 parts by mass of the neopentyl glycol caprylic capric acid mixed ester added. A grease composition for a precision instrument was obtained in the same manner as in example 1-1, except that this lithium soap grease was used.

The grease composition for precision instruments had a viscosity of 1500 mPas at 25 ℃ and was in a liquid state.

[ examples 1 to 6]

As the ether oil (A-3), an alkyl-substituted diphenyl ether (product name: Moresco Hilube LB32, manufactured by Sonmura Petroleum Co., Ltd.) was used in place of the paraffin-based hydrocarbon oil (A-1). A base grease containing alkyl-substituted diphenyl ether (85 mass%) and lithium 12-hydroxystearate soap (15 mass%) was prepared. Next, alkyl-substituted diphenyl ether was further added to the base grease and mixed to obtain a lithium soap grease. Here, the above base grease was used in an amount of 10 parts by mass relative to 90 parts by mass of the alkyl-substituted diphenyl ether added. A grease composition for a precision instrument was obtained in the same manner as in example 1-1, except that this lithium soap grease was used.

The grease composition for precision instruments had a viscosity of 1500 mPas at 25 ℃ and was in a liquid state.

Examples 1-7 to 1-9

A grease composition for precision instruments was obtained in the same manner as in example 1-1, except that the neutral phosphite (B-2) was added in an amount of 0.1 mass%, 10 mass%, or 20 mass% to 100 mass% of the grease composition for precision instruments.

The grease composition for precision instruments had a viscosity of 1500 mPas at 25 ℃ and was in a liquid state.

Examples 1-10 to 1-15

The compounds of Table 1 below were used in place of 4, 4' -butylidenebis (3-methyl-6-tert-butylphenyl) -ditridecyl phosphite (R) as the neutral phosphite (B-2)^b21～R^b24Tridecyl radical, R^b25、R^b27Methyl, R^b26、R^b28Tert-butyl radical, R^b291Hydrogen atom, R^b292An n-propyl group), and a grease composition for a precision instrument was obtained in the same manner as in example 1-1.

[ Table 1]

TABLE 1

Examples	Rb21～Rb24	Rb25、Rb27	Rb26、Rb28	Rb291	Rb292
						1-10	Decyl radical	Methyl radical	Tert-butyl radical	Hydrogen atom	N-propyl radical
1-11	Hexadecyl radical	Methyl radical	Tert-butyl radical	Hydrogen atom	N-propyl radical
						1-12	Tridecyl radical	N-propyl radical	Tert-butyl radical	Hydrogen atom	N-propyl radical
1-13	Tridecyl radical	Methyl radical	Isopropyl group	Hydrogen atom	N-propyl radical
						1-14	Tridecyl radical	Methyl radical	Tert-butyl radical	Hydrogen atom	N-pentyl group
1-15	Tridecyl radical	Methyl radical	Tert-butyl radical	Ethyl radical	N-propyl radical

The grease composition for precision instruments had a viscosity of 1500 mPas at 25 ℃ and was in a liquid state.

[ examples 1 to 16]

A grease composition for a precision instrument was obtained in the same manner as in example 1-2, except that PTFE particles as a solid lubricant were not used.

The grease composition for precision instruments had a viscosity of 1000 mPas at 25 ℃ and was in a liquid state.

[ examples 1 to 17]

A grease composition for precision instruments was obtained in the same manner as in example 1-1, except that the diphenylamine derivative and bis (2,2,6, 6-tetramethyl-1- (octyloxy) piperidin-4-yl) sebacate as the antioxidant (C) were not used.

The grease composition for precision instruments had a viscosity of 1500 mPas at 25 ℃ and was in a liquid state.

[ example 2-1]

A grease composition for precision instruments was obtained in the same manner as in example 1-1 except that 4,4 '-butylidenebis (3-methyl-6-tert-butylphenyl) -ditridecyl phosphate as the neutral phosphate (B-1) was used in place of 4, 4' -butylidenebis (3-methyl-6-tert-butylphenyl) -ditridecyl phosphite as the neutral phosphite (B-2).

The grease composition for precision instruments had a viscosity of 1500 mPas at 25 ℃ and was in a liquid state.

[ examples 2-2 to 2-4]

A grease composition for precision instruments was obtained in the same manner as in example 2-1, except that the neutral phosphate ester (B-1) was added in an amount of 0.1 mass%, 10 mass%, and 20 mass% to 100 mass% of the grease composition for precision instruments.

The grease composition for precision instruments had a viscosity of 1500 mPas at 25 ℃ and was in a liquid state.

[ examples 2-5 to 2-10]

Instead of 4, 4' -butylidenebis (3-methyl-6-tert-butylphenyl) as the neutral phosphate (B-1), the compounds of Table 2 below were used) Bis (tridecyl) phosphite (R)^b11～R^b14Tridecyl radical, R^b15、R^b17Methyl, R^b16、R^b18Tert-butyl radical, R^b191Hydrogen atom, R^b192N-propyl group), a grease composition for a precision instrument was obtained in the same manner as in example 2-1.

[ Table 2]

TABLE 2

Examples	Rb11～Rb14	Rb15、Rb17	Rb16、Rb18	Rb191	Rb192
						2-5	Decyl radical	Methyl radical	Tert-butyl radical	Hydrogen atom	N-propyl radical
2-6	Hexadecyl radical	Methyl radical	Tert-butyl radical	Hydrogen atom	N-propyl radical
						2-7	Tridecyl radical	N-propyl radical	Tert-butyl radical	Hydrogen atom	N-propyl radical
2-8	Tridecyl radical	Methyl radical	Isopropyl group	Hydrogen atom	N-propyl radical
						2-9	Tridecyl radical	Methyl radical	Tert-butyl radical	Hydrogen atom	N-pentyl group
2-10	Tridecyl radical	Methyl radical	Tert-butyl radical	Ethyl radical	N-propyl radical

The grease composition for precision instruments had a viscosity of 1500 mPas at 25 ℃ and was in a liquid state.

[ example 3-1]

A base grease was prepared which contained an alpha-olefin polymer having 30 to 50 carbon atoms (kinematic viscosity at 100 ℃ C. of 6cSt) (85 mass%) as a paraffin-based hydrocarbon oil (A-1) and a diurea compound (U) (15 mass%) represented by the following formula. Subsequently, a trimer of 1-decene (kinematic viscosity at 100 ℃ C. of 5cSt) was further added to the base grease, and mixed to obtain a urea grease. Here, the base grease was used in an amount of 10 parts by mass relative to 90 parts by mass of the trimer of 1-decene added.

To this urea grease, 4' -butylidenebis (3-methyl-6-tert-butylphenyl) -ditridecyl phosphite as a neutral phosphite (B-2), PTFE particles (having a primary particle diameter of 0.5 to 8 μm) as a solid lubricant, a diphenylamine derivative (trade name Irganox L57, manufactured by Ciba Specialty Chemicals) as an antioxidant (C), and bis (2,2,6, 6-tetramethyl-1- (octyloxy) piperidin-4-yl) sebacate were added to obtain a grease composition for precision instruments. Here, these components were added to 100 mass% of the grease composition for precision instruments so as to contain 5 mass% of neutral phosphite (B-2), 10 mass% of solid lubricant, 0.5 mass% of diphenylamine derivative, and 0.5 mass% of bis (2,2,6, 6-tetramethyl-1- (octyloxy) piperidin-4-yl) sebacate.

The grease composition for precision instruments had a viscosity of 1500 mPas at 25 ℃ and was in a liquid state.

[ examples 3-2 ]

A base grease was prepared which contained an alpha-olefin polymer having 30 to 50 carbon atoms (kinematic viscosity at 100 ℃ C. of 6cSt) (85 mass%) as a paraffin hydrocarbon oil (A-1) and a diurea compound (U) (15 mass%). Subsequently, a trimer of 1-decene (kinematic viscosity at 100 ℃ C. of 5cSt) was further added to the base grease, and mixed to obtain a urea grease. Here, the base grease was used in an amount of 20 parts by mass relative to 80 parts by mass of the trimer of 1-decene added.

A grease composition for a precision instrument was obtained in the same manner as in example 3-1, except that the urea grease thus obtained was used.

The grease composition for precision instruments had a mixing consistency of 440 measured according to JIS K22207, and was pasty.

[ examples 3 to 3]

A base grease was prepared which contained an alpha-olefin polymer having 30 to 50 carbon atoms (kinematic viscosity at 100 ℃ C. of 6cSt) (85 mass%) as a paraffin hydrocarbon oil (A-1) and a diurea compound (U) (15 mass%). Subsequently, a trimer of 1-decene (kinematic viscosity at 100 ℃ C. of 5cSt) was further added to the base grease, and mixed to obtain a urea grease. Here, the base grease was used in an amount of 165 parts by mass relative to 30 parts by mass of the trimer of 1-decene added.

A grease composition for a precision instrument was obtained in the same manner as in example 3-1, except that the urea grease thus obtained was used.

The grease composition for precision instruments had a mixing consistency of 27.9 as measured in accordance with JIS K22207, and was in the form of a semisolid.

[ evaluation method and evaluation results ]

The grease composition for precision instruments obtained in examples was applied to the sliding mechanisms of the sliding parts of a timepiece movement (product of Sichuan timepiece Co., Ltd. #2035, wheel train part: made of metal (mainly made of brass and iron)) to produce a timepiece.

These timepieces passed a 12 year accelerated test of slip torque at normal and low temperatures. Specifically, the acceleration test at normal temperature was performed by pulling out the crown at 25 ℃ in a state of timepiece alignment, and continuously rotating the crown for 2.4 hours. In addition, the acceleration test at low temperature was carried out by pulling out the crown at-50 ℃ in a timepiece-aligned state and continuously rotating the crown for 2.4 hours. The torque reduction rate in the acceleration test at normal temperature and low temperature was determined. The results are shown in Table 3.

[ Table 3]

TABLE 3

Table 3 (continuation)

Table 3 (continuation)

Table 3 (continuation)

The grease compositions for precision instruments obtained in the examples were held at 90 ℃ for 1000 hours, and the weight change rate (evaporation rate) of the grease compositions for precision instruments before and after holding was determined. The evaporation rate of the grease composition for precision instruments was 0.05 wt%.