JP2016150954A - Lubricant composition containing lubricant base oil and liquid crystal grease compound, and mechanical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, e.g., a lubricant composition whose available applications are widened by reducing evaporation loss of a lubricant base oil.SOLUTION: A lubricant composition contains a lubricant base oil and a liquid crystal compound represented by the general formula (1), where groups A, B and W represent prescribed groups.SELECTED DRAWING: None

Description

  The present invention relates to a lubricant composition in which the evaporation loss of the lubricating base oil is reduced by including a predetermined liquid crystal compound in the lubricating base oil.

  Lubricants are liquids that are more viscous and have a stronger coating than water, and have a function to reduce friction between objects, and are used to reduce friction between machine elements of machinery and equipment. Is done. The general composition of the lubricant is to add additives for imparting various properties to the base oil.

  Such a lubricant is required to have various characteristics according to the use environment of the machine and the like used. For example, long-term viscosity stability, oxidation resistance, corrosion resistance, and viscosity stability against temperature changes.

  Furthermore, due to various technological innovations in recent years, in various mechanical devices, machine elements have become smaller, lighter, faster and more complicated, and the characteristics required of lubricants have increased. For example, in addition to the above characteristics, a low coefficient of friction, wear resistance, durability, low temperature fluidity, high temperature stability, etc. are required.

  Various lubricants have been proposed as lubricants that can meet such various requirements, and it has also been proposed to use liquid crystal compounds as lubricants (Patent Documents 1 to 4). The liquid crystal compound is generally a compound having a rigid core portion (mesogen group) and a flexible chain portion.

JP 2006-257384 A JP-A-6-128582 JP 2005-139398 A JP 2008-214603 A

  By the way, with the miniaturization, weight reduction, high-speed rotation, and complexity of machine elements in mechanical devices, the environment in which the lubricant is used is diversified. For example, lubricants are used in various environments depending on applications such as high temperature, low temperature, high shear, high pressure, and low pressure.

  Since it is used in various environments as described above, for example, under normal conditions such as normal temperature and normal pressure, even if the lubricant is excellent in the above various characteristics, the base oil is used in a special environment such as high temperature. Ingredients may evaporate.

  Due to the above evaporation problem, some useful lubricants have been greatly limited in their use, and new lubricants that can be used even at high temperatures have been developed.

  On the other hand, an object of this invention is to provide the lubricant composition etc. which expanded the use which can be used by reducing the evaporation loss of lubricant base oil.

  As a result of diligent studies to solve the above problems, the present inventor added a liquid crystal compound having a predetermined chain structure and a rigid core structure to the lubricating base oil, thereby reducing the evaporation loss of the base oil, The present inventors have found that the use as a lubricant can be expanded and have completed the present invention.

That is, the gist of the present invention is as follows.
<1> A lubricant composition comprising a lubricating base oil and a liquid crystal compound represented by the following general formula (1):

[Where:
The group A and the group B are the same or different and may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and may have a branched alkyl group having 1 to 20 carbon atoms; a fluorine atom, a hydroxyl group or An alkenyl group having 2 to 20 carbon atoms which may be substituted with a cyano group and which may have a branch; a carbon which may be substituted with a fluorine atom, a hydroxyl group or a cyano group and which may have a branch An alkynyl group of 2 to 20; or a monovalent organic residue represented by the following general formula (2):

(In the formula, R ¹¹ is optionally substituted with a fluorine atom, a hydroxyl group or a cyano group, and may have a branched alkyl group having 1 to 20 carbon atoms; substituted with a fluorine atom, a hydroxyl group or a cyano group. An alkenyl group having 2 to 20 carbon atoms which may be branched or optionally branched; alternatively, it may be substituted with a fluorine atom, a hydroxyl group or a cyano group and may have a branched carbon number 2 -20 alkynyl groups,
R ¹² and R ¹⁵ are each independently a hydrogen atom; a fluorine atom, a hydroxyl group or a cyano group, which may be substituted and optionally branched, an alkyl group having 1 to 20 carbon atoms; a fluorine atom, a hydroxyl group Or an alkenyl group having 2 to 20 carbon atoms which may be substituted with a cyano group and which may have a branch; or a branch which may be substituted with a fluorine atom, a hydroxyl group or a cyano group Or an alkynyl group having 2 to 20 carbon atoms,
R ¹³ represents a single bond; a C 1-20 alkylene group which may be substituted with a fluorine atom, a hydroxyl group or a cyano group; or a fluorine atom, a hydroxyl group or a cyano group; An alkenylene group having 2 to 20 carbon atoms which may be substituted or branched;
R ¹⁴ and R ¹⁶ are each independently an alkylene group having 1 to 20 carbon atoms which may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and may be branched; or a fluorine atom, a hydroxyl group or It is a C2-C20 alkenylene group which may be substituted with a cyano group and may have a branch. )
The group W is a divalent group selected from the group consisting of a divalent tetralin group which may be substituted, a divalent polycyclic aromatic group which may be substituted, and a group represented by the following general formula (I). Is a mesogenic group of:

(Wherein, ring D, ring E and ring F are each independently a benzene ring, cyclohexane ring, cyclohexene ring, pyridine ring, pyrimidine ring, dioxane ring, tetralin ring or polycyclic aromatic ring,
Y is independently hydrogen atom, deuterium atom, alkyl group having 1 to 8 carbon atoms, alkoxy group, alkenyl group, alkenyloxy group, alkynyl group, alkynyloxy group, alkoxyalkyl group, alkanoyloxy group, alkoxycarbonyl. A group, a halogen atom, or a cyano group,
s1 to s3 are each independently an integer up to 1, or the number of sites to which a substituent of ring D, ring E or ring F can be bonded;
when s1 to s3 are 2 or more, a plurality of Y bonded to the same ring may be the same or different;
Z ₁ and _{Z 2} are each independently a single _{bond, -CO-O -, - O} -CO -, - CH 2 O -, - OCH 2 -, - CH 2 CH 2 -, - CH = CHCH 2 O-, _{-CH = CH -, - CF 2} O -, - OCF 2 -, - S -, - SO -, - SO 2 - or a -C≡C-,
r is 0, 1 or 2;
When r is 2, two Z ₁ may be the same or different, and the two rings D may be the same or different, and are bonded to the two rings D, respectively. Y may be the same or different. ]].

  <2> In the general formula (1), the group A and the group B may be the same or different and may be substituted with a fluorine atom, a hydroxyl group, or a cyano group, and may have a branch. The lubricant composition according to <1>, which is 20 alkyl groups or an organic residue represented by the general formula (2).

<3> In the general formula (2), R ¹¹ is an alkyl group having 1 to 20 carbon atoms which may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and may have a branch, and R ¹² And R ¹⁵ are each independently a hydrogen atom; or a C 1-20 alkyl group which may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and may be branched, and R ¹³ , <1> or <2 wherein R ¹⁴ and R ¹⁶ are each independently an alkylene group having 1 to 20 carbon atoms which may be substituted with a fluorine atom, a hydroxyl group or a cyano group and which may have a branch. > The lubricant composition as described in>.

<4> In the general formula (I), ring D, ring E and ring F each independently represent a benzene ring, a cyclohexane ring, a dioxane ring, a tetralin ring or a polycyclic aromatic ring, and Y each independently represents hydrogen. The lubricant according to any one of <1> to <3>, which represents an atom or a halogen atom, Z ₁ and Z ₂ each independently represents a single bond or —CO—O—, and r represents 0 or 1. Composition.

<5> The lubricant composition according to any one of <1> to <4>, wherein in the general formula (2), R ¹⁴ and R ¹⁶ are the same group.

  <6> The lubricant composition according to any one of <1> to <5>, wherein the content of the liquid crystal compound represented by the formula (1) in the lubricant composition is 5% by weight or more. object.

  <7> Liquid crystal grease containing the lubricant composition according to any one of <1> to <6>.

  <8> The lubricant composition according to any one of <1> to <6>, which is disposed on at least a part of a contact surface of the plurality of machine elements that are in contact with each other and relatively move, or <7 > The liquid crystal grease described in the above.

  According to the present invention, it is possible to reduce the evaporation loss of the lubricating base oil and greatly expand its usable applications.

FIG. 1 shows the results of examining the weight loss of a lubricant composition of the present invention, the lubricating base oil compound 1 and a comparative mixture in a constant temperature bath at 100 ° C. in a specific time in the examples.

  Hereinafter, the present invention will be described in detail. The lubricant composition of the present invention contains a lubricating base oil and a liquid crystal compound represented by the above general formula (1). Hereinafter, the lubricating base oil and the liquid crystal compound will be described in this order.

[Lubricating base oil]
The lubricant composition of the present invention contains a lubricating base oil. The lubricating base oil is not particularly limited as long as it has a lubricating function, and various base oils can be used in the present invention, including conventionally used lubricating base oils. Lubricating base oils may evaporate in various environments, and some of them have particularly large evaporation loss. In particular, the use of them as a lubricant has been limited, but in the present invention, the evaporation loss of the lubricating base oil is greatly reduced by the coexistence of the liquid crystal compound described below. Therefore, the lubricant composition of the present invention can be used stably over a long period of time because the evaporation loss of the lubricating base oil is greatly suppressed even in various special environments such as high temperatures, low pressures, and clean rooms.

  Specific examples of the lubricating base oil include a liquid crystal compound having a lubricating function, mineral oil, highly refined mineral oil, organic acid ester, phosphate ester, silicone oil, olefin oligomer, poly α-olefin, polyalkylene glycol, polyol ester, Examples thereof include alkylbenzene and derivatives thereof, fluorine oil, alkylphenyl ether oil, alkylbiphenyl oil, alkyldiphenyl ether oil, and polyphenyl ether oil.

  Among these, in the lubricating base oil having a large evaporation loss, the effect of suppressing the evaporation of the lubricating base oil of the present invention and widening the use of the lubricant can be suitably achieved. Here, “large evaporation loss” means that the weight reduction rate of the lubricating base oil is 5% or more after 500 hours in an atmosphere of 100 ° C. at 1 atm.

  Further, as will be described later, the lubricating base oil generally has a chain structure, but when the chain structure enters the structure in which the liquid crystal compound represented by the general formula (1) is aligned, It is thought that it is trapped by interaction and becomes difficult to evaporate. In view of this, the lubricating base oil has a chain structure that easily penetrates into the oriented structure of the liquid crystal compound, such as a straight chain structure, or a chain structure similar to the tail portion of the liquid crystal compound (size, polarity, chain shape). And the like have a similar chain structure).

  In addition, as a base oil in which the effect of the present invention is remarkably exhibited (evaporation loss is greatly reduced by a combination with a liquid crystal compound represented by the general formula (1) described later), the following general formula (3) is used. And the compounds represented.

(About R ¹ and R ⁶ )
In General Formula (3), R ¹ and R ⁶ are each independently an alkyl group having 1 to 20 carbon atoms that may be substituted with a fluorine atom, a hydroxyl group, or a cyano group, and may have a branch; An alkenyl group having 2 to 20 carbon atoms which may be substituted with an atom, a hydroxyl group or a cyano group; or a branch which may be substituted with a fluorine atom, a hydroxyl group or a cyano group It is a C2-C20 alkynyl group which may have.

Examples of the alkyl group include butyl, pentyl, 2-ethylhexyl, hexyl, heptyl, 2-methylheptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl Groups,
Examples of the alkenyl group include butenyl group, pentenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group,
Examples of the alkynyl group include a butynyl group, a pentynyl group, a heptynyl group, an octynyl group, a nonynyl group, a decynyl group, an undecynyl group, a dodecynyl group, a tridecynyl group, and a tetradecynyl group.

(About R ³ and R ⁴ )
In the general formula (3), R ³ and R ⁴ are each independently a hydrogen atom; may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and may have a branch, and may have 1 to 20 carbon atoms. An alkyl group; an alkenyl group having 2 to 20 carbon atoms which may be substituted with a fluorine atom, a hydroxyl group or a cyano group; or substituted with a fluorine atom, a hydroxyl group or a cyano group; Or an alkynyl group having 2 to 20 carbon atoms which may be branched.

Examples of the alkyl group include a methyl group, an ethyl group, a 2-methylpropyl group, a propyl group, a butyl group, and a t-butyl group.
Examples of the alkenyl group include ethenyl group, propenyl group, butenyl group,
Examples of the alkynyl group include ethynyl group, propynyl group, and butynyl group.

(About R ² and R ⁵ )
In the general formula (3), R ² and R ⁵ are each independently an alkylene group having 1 to 20 carbon atoms which may be substituted with a fluorine atom, a hydroxyl group or a cyano group and may have a branch; Or it is the C2-C20 alkenylene group which may be substituted by the fluorine atom, the hydroxyl group, or the cyano group, and may have a branch.

Examples of the alkylene group include methylene group, ethylene group, propylene group, butylene group,
Examples of the alkenylene group include an ethynylene group, a propynylene group, and a butynylene group.

(About m)
In the said General formula (3), m is an integer of 1-6. When m is 2 or more, there are a plurality of parenthesized units with a subscript m, and there are a plurality of R ² , R ³ , R ⁴ and R ⁵ , respectively. R ^{2 to} each other, R ^{3 to} each other, R ^{4 to} each other, and R ^{5 to} each other may be the same as or different from each other.

<Reduction in evaporation loss>
In the lubricant composition of the present invention, the evaporation loss can be reduced by combining, for example, the various lubricating base oils described above with the liquid crystal compound represented by the general formula (1) described later.

<Content of lubricating base oil>
The content of the lubricating base oil in 100% by weight of the lubricant composition of the present invention is appropriately selected from a conventionally known range and is not particularly limited, but the lubricity of the composition is not particularly limited. From the viewpoint, it is usually 30% by weight or more, preferably 40 to 99% by weight.

[Liquid Crystal Compound Represented by General Formula (1)]
Next, the liquid crystal compound represented by the general formula (1) (hereinafter also referred to as liquid crystal compound 1), which is an essential component of the lubricant composition of the present invention, will be described. The compound is represented by the following general formula (1).

  As will be described later, in the liquid crystal compound 1, the groups A and B are flexible tail portions, and the group W has a rigid core structure (liquid crystal forming element). Since it has such a chemical structure, the liquid crystal compound 1 can form a liquid crystal phase.

  In the liquid crystal phase, the molecules of the plurality of liquid crystal compounds 1 have a regular intermolecular arrangement structure in which the groups W are substantially overlapped with the groups W, and the groups A and B are overlapped with each other between the groups A and B.

  It is considered that the lubricating base oil is trapped by entering the chain structure of the lubricating base oil into such an ordered intermolecular arrangement structure, and as a result, the evaporation loss of the lubricating base oil is greatly reduced. In addition, there are various types of chain structures of the lubricating base oil. In the present invention, the portion that becomes an intermolecular alignment structure that traps this, particularly the tail portion of the group A or the group B of the liquid crystal compound 1, By designing to match the chain structure of the lubricating base oil to be combined, it is considered that the evaporation loss of the lubricating base oil can be suitably reduced. Note that “matching to the chain structure of the lubricating base oil” means that the chain structure of the lubricating base oil easily enters the intermolecular alignment structure of the liquid crystal compound 1, for example, the group A or group B of the liquid crystal compound 1. Is similar to the chain structure of the lubricating base oil in terms of size, polarity and shape.

  Hereinafter, each group in the general formula (1) representing the liquid crystal compound 1 will be described.

<About Group A and Group B>
In the general formula (1), the group A and the group B are the same or different and may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and may have a branched alkyl group having 1 to 20 carbon atoms. A C2-C20 alkenyl group which may be substituted with a fluorine atom, a hydroxyl group or a cyano group; a branch which may be substituted with a fluorine atom, a hydroxyl group or a cyano group; An alkynyl group having 2 to 20 carbon atoms which may have; or a monovalent organic residue represented by the following general formula (2).

  The group A and the group B constitute a tail portion in the liquid crystal compound 1, and depending on the type of the liquid crystal compound 1, the liquid crystal compounds 1 or components of the liquid crystal compound 1 and the lubricant composition of the present invention described later (for example, a lubricating group) The intermolecular force with the oil), and particularly the lubricity base oil, can adjust the ease of entering the intermolecular arrangement structure.

  From the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1, the alkyl group preferably has 4 to 14 carbon atoms. Examples of such alkyl groups are butyl, pentyl, 2-ethylhexyl, hexyl, heptyl, 2-methylheptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl. And a tetradecyl group.

  The alkenyl group preferably has 4 to 14 carbon atoms from the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1. Examples of such alkenyl groups include butenyl, pentenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, and tetradecenyl.

  From the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1, the alkynyl group preferably has 4 to 14 carbon atoms. Examples of such alkynyl groups include butynyl, pentynyl, heptynyl, octynyl, noninyl, decynyl, undecynyl, dodecynyl, tridecynyl, and tetradecynyl groups.

  Next, each group in the general formula (2) will be described.

(For ^{R 11)}
In the general formula (2), R ¹¹ may be substituted with a fluorine atom, a hydroxyl group, or a cyano group, and may have a branched alkyl group having 1 to 20 carbon atoms; a fluorine atom, a hydroxyl group, or An alkenyl group having 2 to 20 carbon atoms which may be substituted with a cyano group and which may be branched; alternatively, it may be substituted with a fluorine atom, a hydroxyl group or a cyano group and may be branched. It is a good C2-C20 alkynyl group.

  From the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1, the alkyl group preferably has 1 to 12 carbon atoms. Examples of such alkyl groups are methyl, ethyl, propyl, butyl, pentyl, 2-ethylhexyl, hexyl, heptyl, 2-methylheptyl, octyl, nonyl, decyl. , Undecyl group and dodecyl group.

  The alkenyl group preferably has 2 to 12 carbon atoms from the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1. Examples of such alkenyl groups include ethenyl, propenyl, butenyl, pentenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl.

  From the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1, the alkynyl group preferably has 2 to 12 carbon atoms. Examples of such alkynyl groups include ethynyl, propynyl, butynyl, pentynyl, heptynyl, octynyl, nonynyl, decynyl, undecynyl, and dodecynyl.

As R ¹¹ explained above, from the viewpoint of the compatibility of the liquid crystal compound 1 with the lubricating base oil, it may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and may have a branch. ˜20 alkyl groups are preferred.

(About R ¹² and R ¹⁵ )
In the general formula (2), R ¹² and R ¹⁵ are each independently a hydrogen atom; a fluorine atom, a hydroxyl group, or a cyano group, which may have a branch and may have 1 to 20 carbon atoms. An alkyl group; an alkenyl group having 2 to 20 carbon atoms which may be substituted with a fluorine atom, a hydroxyl group or a cyano group; or substituted with a fluorine atom, a hydroxyl group or a cyano group; Or an alkynyl group having 2 to 20 carbon atoms which may be branched.

  From the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1, the alkyl group preferably has 1 to 4 carbon atoms. Examples of such an alkyl group include a methyl group, an ethyl group, a 2-methylpropyl group, a propyl group, a butyl group, and a t-butyl group.

  The alkenyl group preferably has 2 to 4 carbon atoms from the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1. Examples of such alkenyl groups include ethenyl, propenyl, and butenyl groups.

  From the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1, the alkynyl group preferably has 2 to 4 carbon atoms. Examples of such alkynyl groups include ethynyl group, propynyl group, and butynyl group.

R ¹² and R ¹⁵ described above may be substituted with a hydrogen atom, a fluorine atom, a hydroxyl group, or a cyano group from the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1 and have a branch. An alkyl group having 1 to 20 carbon atoms which may be used is preferable.

(For ^{R 13)}
In the general formula (2), R ¹³ is a single bond; a C 1-20 alkylene group which may be substituted with a fluorine atom, a hydroxyl group or a cyano group and may have a branch; It is a C2-C20 alkenylene group which may be substituted with an atom, a hydroxyl group or a cyano group and may have a branch.

  From the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1, the alkylene group preferably has 1 to 4 carbon atoms. Examples of such an alkylene group include a methylene group, an ethylene group, a propylene group, and a butylene group.

  The alkenylene group preferably has 2 to 4 carbon atoms from the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1. Examples of such alkenylene groups include ethynylene groups, propynylene groups, and butynylene groups.

From the viewpoint of compatibility of the liquid crystal compound 1 with the lubricating base oil, R ¹³ described above may be substituted with a fluorine atom, a hydroxyl group, or a cyano group, and may have a branch. ~ 20 alkylene groups are preferred.

(About R ¹⁴ and R ¹⁶ )
In the general formula (2), R ¹⁴ and R ¹⁶ are each independently an alkylene group having 1 to 20 carbon atoms which may be substituted with a fluorine atom, a hydroxyl group or a cyano group and may have a branch; Or it is the C2-C20 alkenylene group which may be substituted by the fluorine atom, the hydroxyl group, or the cyano group, and may have a branch.

  From the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1, the alkylene group preferably has 2 to 4 carbon atoms. Examples of such an alkylene group include an ethylene group, a propylene group, and a butylene group.

  The alkenylene group preferably has 2 to 4 carbon atoms from the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1. Examples of such alkenylene groups include ethynylene groups, propynylene groups, and butynylene groups.

R ¹⁴ and R ¹⁶ described above may be substituted with a fluorine atom, a hydroxyl group or a cyano group from the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1, or may have a branch. An alkylene group having 1 to 20 carbon atoms is preferred. In addition, these groups are preferably the same group from the viewpoint of easy production of the liquid crystal compound 1.

(About group A and group B)
In the above general formula (1) showing the structure of the liquid crystal compound 1, the group A and the group B are, as explained above, a predetermined alkyl group, alkenyl group, alkynyl group or a monovalent organic residue of the general formula (2). It is.

  Among these, as the group A and the group B, from the viewpoint of compatibility with the lubricating base oil of the liquid crystal compound 1, the alkyl group and the organic residue of the general formula (2) are preferable (in this case, the group A and the group A). The groups B may be the same or different).

<About Group W>
In the general formula (1), the group W is a divalent tetralin group which may be substituted, a divalent polycyclic aromatic group which may be substituted, and a group represented by the following general formula (I): A divalent mesogen group selected from the group consisting of

The group W has a rigid structure and is a liquid crystal forming element (core portion) in the liquid crystal compound 1.

  The polycyclic aromatic group is an aromatic group having two or more aromatic rings. These two or more aromatic rings may be bonded by a single bond such as biphenyl, or may be bonded in a condensed ring state such as naphthalene. Further, the ring-constituting atoms of the aromatic ring may be only carbon atoms or may contain heteroatoms.

  Examples of such polycyclic aromatic groups include the following.

  Examples of the substituent in the tetralin group and the polycyclic aromatic group include a deuterium atom, a fluorine atom, and an alkyl group having 1 to 3 carbon atoms.

  In the general formula (I), Ring D, Ring E and Ring F are each independently a benzene ring, cyclohexane ring, cyclohexene ring, pyridine ring, pyrimidine ring, dioxane ring, tetralin ring or polycyclic aromatic ring. The polycyclic aromatic ring is the same as the polycyclic aromatic group described above as a candidate for the group W.

  In the general formula (I), each Y is independently a hydrogen atom, a deuterium atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or carbon. C2-C8 alkenyloxy group, C2-C8 alkynyl group, C2-C8 alkynyloxy group, C2-C8 alkoxyalkyl group, C2-C8 alkanoyloxy group, carbon number 2-8 alkoxycarbonyl groups, a halogen atom, or a cyano group is represented. Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

  In the above general formula (I), s1 to s3 are each independently an integer up to 1, or the number of sites to which the substituents of ring D, ring E or ring F can bind. For example, when the ring D is a benzene ring, s1 is an integer of 1 to 4, and when the ring D is a naphthalene ring, s1 is an integer of 1 to 6.

  Here, when s1 to s3 is 2 or more, a plurality of Ys are bonded to each of the rings D to F, but a plurality of Ys bonded to the same ring are the same or different. Also good. Of course, Y bonded to different rings may be the same or different.

In the general formula (I), Z ₁ and Z ₂ are each independently a single bond, —CO—O—, —O—CO—, —CH ₂ O—, —OCH ₂ —, —CH ₂ CH ₂ —, —CH═CHCH ₂ O—, —CH═CH—, —CF ₂ O—, —OCF ₂ —, —S—, —SO—, —SO ₂ — or —C≡C—, where r is 0, 1 or 2 is represented.

Here, when r is 2, two rings D and Z ₁ exist, but two Z ₁ may be the same or different, and two rings D exist. May be the same or different. Further, Ys bonded to the two rings D may be the same or different.

  Further, Y is preferably a hydrogen atom, a deuterium atom, a halogen atom, a methyl group, or an ethyl group, more preferably a hydrogen atom, a deuterium atom, or a halogen atom, from the viewpoint of the temperature characteristics of the liquid crystal, A halogen atom is particularly preferred.

As Z ₁ and Z ₂ , from the viewpoint of the temperature characteristics of the liquid crystal, a single bond, —CO—O—, —O—CO—, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH _{2 are used.} -, - SO ₂ -, more preferably a single bond, -CO-O-, and _-CH 2 O-are more preferably a single bond and -CO-O- being particularly preferred.

  As ring D, ring E and ring F, a benzene ring, a cyclohexane ring, a dioxane ring, a tetralin ring and a polycyclic aromatic ring are preferable. R is preferably 0 or 1.

  Specific examples of the divalent mesogen group represented by the general formula (I) described above include the following divalent organic residues.

<About Group A and Group B>
As described above, since the group A and the group B are selected from the same option in the general formula (1), the group A and the group B may be the same group. In such a case, the liquid crystal compound 1 is preferable from the viewpoint of production because the number of types of raw materials used in the production of the liquid crystal compound 1 described later is small.

  On the other hand, when the group A and the group B are different groups, the types of production raw materials to be used are larger than those in the case where they are the same, but the temperature range in which the lubricant composition of the present invention can be used will be described later. It may be advantageous in terms.

<Content of liquid crystal compound 1>
The content of the liquid crystal compound 1 described above in 100% by weight of the lubricant composition of the present invention is appropriately selected as long as the evaporation loss of the lubricating base oil can be reduced, but is usually 1% by weight or more. It is preferably 5% by weight or more.

<Method for producing liquid crystal compound 1>
Next, the manufacturing method of the liquid crystal compound 1 demonstrated above is demonstrated. The method for producing the liquid crystal compound 1 is not particularly limited, and the liquid crystal compound 1 can be produced by combining known reactions.

  The synthesis of the liquid crystal compound 1 can be easily performed by sequentially or simultaneously bonding the group W (core portion) described in the general formula (1) and the groups A or B on both sides thereof by an ether bond. Can do.

  As the reaction for bonding the group W and the group A or the group W and the group B by the ether bond, an alcohol compound (A-OH or B-OH), a phenol compound (HO-W-OH), an alkali metal or an alkali metal is used. A method of reacting with a halogen compound (AX, BX or XWX (X is a halogen atom such as a chlorine atom, a bromine atom or an iodine atom)) using an alcoholate can be used.

  Examples of the alkali metal include potassium carbonate, potassium hydroxide, and sodium hydroxide. Examples of the alkali metal alcoholate include sodium ethylate, sodium methylate, tert-butoxy sodium, and tert-butoxy potassium.

  For these reactions, various conventionally known organic solvents can be used. For example, diethyl ether, tetrahydrofuran (THF), acetone, and toluene can be used.

  In addition, when the liquid crystal compound 1 is a compound in which the group A and the group B are the same group in the general formula (1), the compound and the group B that become the group A in the general formula (1) described above. Therefore, the synthesis of the liquid crystal compound 1 is easy because two kinds of raw materials are sufficient.

(Mixture formation)
On the other hand, when the group A and the group B are different groups, the compound X′-W—X ′ (core raw material) to be the group W in the general formula (1) and the compound AX to be the group A ( The raw material 1) is reacted with the compound BX (raw material 2) to be the group B. Here, when these are reacted at the same time, which of the two reaction points of the core raw material reacts with the raw material 1 or 2 becomes a problem of probability, and the reaction point on the left side in the group W of the general formula (1) The raw material 1 or 2 reacts, and the raw material 1 or 2 reacts at the reaction point on the right side to produce a total of four types of compounds. In the general formula (1), when the group W is a group having a symmetrical structure, three types of compounds are generated. The production of the plurality of types of compounds is shown by a reaction formula, for example, as follows.

(X is independently a halogen atom or hydroxyl group, and X ′ is independently a halogen atom or hydroxyl group.)

  The target liquid crystal compound 1 is obtained as a mixture of such a plurality of compounds. As will be described later, the liquid crystal compound 1 itself has lubricity in addition to the effect of reducing the evaporation loss of the lubricating base oil, and the mixture described above can be used as a lubricant in a wider temperature range than the liquid crystal compound 1 alone. Since the mixture exhibits a suitable low viscosity, the mixture can be suitably used in the lubricant composition of the present invention as described later.

[Lubricant composition]
As described above, the lubricant composition of the present invention includes the lubricating base oil and the predetermined liquid crystal compound 1, and at least part of the chain structure of the lubricating base oil enters the intermolecular alignment structure of the liquid crystal compound 1. Be trapped. Thereby, in the lubricant composition of the present invention, the evaporation loss of the lubricating base oil is reduced, and various base oils can be used in a wide range of applications. In particular, the lubricating base oil, which has excellent performance as a lubricating oil, but could not be used under high temperature or low pressure due to high evaporation loss, can be used in those environments according to the present invention. Become.

  Further, the liquid crystal compound 1 not only reduces the evaporation loss of the lubricating base oil but also has a lubricating action. Therefore, the lubricant composition of the present invention is used as a lubricant having particularly excellent lubricity. To get.

  Furthermore, in the present invention, the lubricating base oil that can be used due to its effect of reducing the evaporation loss, and the usable applications of the lubricant composition are wider than those of conventional lubricants. Therefore, the lubricant composition of the present invention can be used for various lubrication applications by appropriately selecting the type of the lubricating base oil according to the properties required according to the application. For example, the lubricant composition of the present invention can be used as a liquid crystal grease by adjusting the viscosity to a predetermined range.

  In addition, since the group W in General formula (1) is various rigid groups, the liquid crystal compound 1 can form a liquid crystal phase. Specifically, the liquid crystal compound 1 usually forms a liquid crystal phase in the range of −20 to 150 ° C. (thermotropic liquid crystal). The liquid crystal phase to be formed may be any of a smectic liquid crystal phase, a nematic liquid crystal phase, a cholesteric liquid crystal phase, and a discotic liquid crystal phase. The presence or absence of liquid crystallinity can be determined by observation using a polarizing microscope.

  The liquid crystal compound 1 can be contained in a lubricating base oil to form a liquid crystal phase.

  In the liquid crystal phase formed in this way, the liquid crystal compound 1 is regularly arranged at the site of the machine element where the lubricant composition is used, and depending on the mechanical impact caused by the rotation of the machine element, the lubricant composition Is considered to be difficult to be scattered. Furthermore, the liquid crystal compound 1 is a substance that forms a liquid crystal phase in a relatively wide temperature range. When used in the form of a mixture as described above, the liquid crystal phase formation temperature range is further widened. Thereby, the temperature range in which the evaporation loss of the lubricating base oil can be reduced is widened, and therefore the lubricant composition of the present invention has a wide temperature range that can be generally used.

  The lubricant composition of the present invention includes the lubricating base oil and the liquid crystal compound 1 as described above. In the lubricant composition of the present invention, one kind may be used as the lubricating base oil, two or more kinds may be used in combination, and the liquid crystal compound 1 is also used in the same manner. Or two or more of them may be used in combination. In addition, about these content, it is as having demonstrated in each term of the lubricating base oil and the liquid crystal compound 1.

<Other ingredients>
Next, the other components that the lubricant composition of the present invention may contain in a range not impairing the effects of the present invention will be described in order. These are basically known substances as components of the lubricant composition, and their contents can be appropriately selected by those skilled in the art within a conventionally known range unless otherwise specified. In addition, any of these components may be used alone or in combination of two or more.

(Liquid crystal compound)
The lubricant composition of the present invention may contain a liquid crystal compound other than the liquid crystal compound 1 described above.

  Examples of such a liquid crystal compound include a liquid crystal compound exhibiting a smectic phase or a nematic phase, an alkyl sulfonic acid, a compound having a Nafion membrane structure, an alkyl carboxylic acid, and an alkyl sulfonic acid.

  The combined use of these components can broaden the temperature range in which the liquid crystal compound contained in the lubricant composition of the present invention forms a liquid crystal phase, and the advantages of the above liquid crystal phase formation can be enjoyed in a wide temperature range. There is sex.

(Other additives)
Additives that can be added to the lubricant composition of the present invention include various additives used in lubricants for various mechanical devices such as bearing oils, gear oils and hydraulic oils, that is, extreme pressure agents, oriented adsorbents, Antiwear agent, antiwear agent, oiliness agent, antioxidant, viscosity index improver, pour point depressant, cleaning dispersant, metal deactivator, corrosion inhibitor, rust inhibitor, antifoaming agent, solid lubricant Etc.

  Examples of the extreme pressure agent include chlorine compounds, sulfur compounds, phosphoric acid compounds, hydroxycarboxylic acid derivatives, and organometallic extreme pressure agents. By adding the extreme pressure agent, the wear resistance of the lubricant composition of the present invention is improved.

  Examples of the alignment adsorbent include organic silanes, organic titanium, and organic aluminum typified by various coupling agents such as a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent. By adding an alignment adsorbent, the liquid crystal alignment of the liquid crystal compound in the lubricant composition of the present invention is strengthened, and the thickness and strength of a film formed from the lubricant composition of the present invention, which will be described later, can be enhanced.

<Method for preparing lubricant composition>
The lubricant composition of the present invention can be prepared by mixing the above-described lubricating base oil, the liquid crystal compound 1 and other components as required by a conventionally known method. An example of the method for preparing the lubricant composition of the present invention is as follows.

  The constituents of the lubricant composition are mixed by a conventional method, and then, if necessary, roll milling, defoaming treatment, filtering treatment, etc. are performed to obtain the lubricant composition of the present invention. Alternatively, the lubricant composition can also be obtained by first mixing the oil component of the lubricant composition, then adding and mixing other components such as additives, and performing the above defoaming treatment as necessary. Can be prepared.

<Use of lubricant composition>
The lubricant composition of the present invention can be used in a wide range of lubricating base oils due to the effect of reducing the evaporation loss of the liquid crystal compound 1 with respect to the lubricating base oil, and therefore has a wide range of applications. In addition, as described above, the liquid crystal compound 1 is a compound that generally forms a liquid crystal phase in a wide temperature range, and forms a liquid crystal phase in a wide temperature range including a low temperature range. Therefore, the lubricant composition of the present invention is used. The possible temperature range is also generally wide. As described above, the lubricant composition can be suitably used as a lubricant in various mechanical devices.

  In general, a mechanical device has a plurality of mechanical elements that move relative to each other in contact with each other. By arranging the lubricant composition of the present invention on at least a part of the contact surface of the mechanical elements, Friction caused by contact can be reduced and relative motion can be smoothed.

  In the present invention, the contact refers not only to the case where a plurality of objects are in direct contact but also to the case where the object is indirectly in contact with some substance such as a film formed by the lubricant composition of the present invention. Including. That is, when the lubricant composition of the present invention is disposed on the contact surfaces of a plurality of machine elements, a film made of the composition is formed between the plurality of machine elements, and direct contact between the machine elements is eliminated. Thereby, wear and seizure due to friction between machine elements can be suitably prevented. Further, the contact of the mechanical element does not necessarily have to be continued without interruption during the relative motion, and there may exist a state in which the mechanical element does not contact in the relative motion like a gear.

  Methods for disposing the lubricant composition of the present invention on the contact surfaces of the plurality of machine elements are known to those skilled in the art. Such methods include, for example, applying the composition to the contact surface, and filling the composition into a certain area in close proximity to the machine element, including the contact surface of the machine element.

  The mechanical elements are elements (parts, etc.) constituting various mechanical devices, which are conventionally lubricated with a lubricant and those that may be lubricated with a lubricant in the future. including.

  The contact surfaces of the plurality of machine elements, more broadly speaking, the contact sites of the machine elements may be flat or curved, and at least a part of such surfaces may have irregularities or holes. May be present. Moreover, surface treatments such as various modifications may be performed on the parts of the machine elements constituting the contact parts of the machine elements. The material of the machine element is not particularly limited, and may be made of any material such as a metal material or an organic / inorganic material. Further, the type of the constituent material may be different between one of the machine elements and the other.

  Examples of the machine device having such various machine elements include transportation machines, processing machines, computer-related equipment, office-related equipment such as copiers, and household products, and the lubricant composition of the present invention. Can be suitably used for lubrication of bearings of these various mechanical devices, for example.

  Specific examples of the bearings include bearings used in electrical equipment for automobiles such as electric fan motors and wiper motors; rolling bearings used in automobile engine accessories such as water pumps and electromagnetic clutch devices, and drive systems; industrial machinery Rolling bearings used in rotating devices such as small to large general-purpose motors for machines; high-speed and high-precision rotating bearings such as spindles for machine tools, motors and rotating devices for household appliances such as air conditioner fan motors and washing machines Rolling bearings used; rolling bearings used in rotating parts of computer-related equipment such as HDD devices and DVD devices; rolling bearings used in rotating parts of office machines such as copying machines and automatic ticket gates; and trains and Axle bearings for freight cars.

  In addition, the lubricant composition of the present invention lubricates resin pulleys used in automobile CVJ devices and electronic / electric control power steering devices, and lubricates mechanical elements of various rolling devices such as linear guides and ball screws. Can be used for

  The lubricant composition of the present invention includes, for example, engine oil, gear oil, automotive hydraulic oil, marine / aircraft lubricating oil, machine oil, turbine oil, hydraulic hydraulic oil, spindle oil, compressor oil, Vacuum pump oil, refrigerating machine oil, lubricant for metal processing, hinge oil, sewing machine oil, sliding surface oil, and HDD platter lubricant (using horizontal magnetic recording system and thermal assist recording technology, etc.) It can also be used for lubricants for magnetic recording media, lubricants for micromachines, lubricants for artificial bones, and the like.

[Grease composition]
The present invention also relates to a grease composition described below, and the grease composition will be described below. The grease composition of the present invention is obtained by adding the above lubricating base oil to the liquid crystal compound 1 represented by the above general formula (1). An example of this is as follows.

  [1] A grease composition comprising a liquid crystal compound represented by the general formula (1) and a lubricating base oil.

  [2] The grease composition according to [1], wherein the content of the lubricating base oil in the grease composition is 0.1 to 50% by weight.

  [3] The grease composition according to [1] or [2], wherein a structure of a side chain of the lubricating base oil is similar to A or B in the general formula (1).

  [4] A machine having a plurality of machine elements that move relative to each other in contact with each other, and the grease composition according to any one of [1] to [3] disposed on at least a part of a contact surface of the machine elements. apparatus.

<Liquid crystal compound 1>
The liquid crystal compound 1 used in the grease composition of the present invention is the same as the liquid crystal compound 1 represented by the general formula (1) used in the lubricant composition of the present invention. Although the liquid crystal compound 1 can reduce the evaporation loss of the lubricating base oil, the liquid crystal compound 1 itself has lubricity and also has a low evaporation loss. Therefore, the liquid crystal compound 1 is preferably used as a lubricant. can do.

  And since the liquid crystal compound 1 has a rigid structure of W in the general formula (1), it has a relatively high viscosity. Therefore, by adding a lubricating base oil to this, the overall viscosity can be lowered to obtain a grease composition that achieves the desired viscosity.

  In the grease composition of the present invention, the liquid crystal compound 1 is a main component, and the liquid crystal compound 1 is usually contained in the grease composition in a proportion of 50 to 99.9% by weight, preferably 70 to 99% by weight. ing. Moreover, the liquid crystal compound 1 may use 1 type, and may use 2 or more types together.

<Lubricating base oil>
The lubricating base oil used in the grease composition of the present invention is the same as the lubricating base oil used in the lubricant composition of the present invention.

  The lubricating base oil has a lower viscosity than the liquid crystal compound 1, and by adding this, the viscosity of the entire grease composition can be adjusted to an appropriate range depending on the application. The lubricating base oil is considered to have an effect of lowering the viscosity by entering the intermolecular arrangement structure of the liquid crystal compound 1 and slightly disturbing the structure.

  From the viewpoint of such action, the lubricating base oil preferably has a structure that easily enters the intermolecular alignment structure of the liquid crystal compound 1. It preferably has a structure similar to B as the main chain or side chain.

  The “similar structure” refers to a structure defined by A and B in the general formula (1).

  The content of the lubricating base oil in the grease composition of the present invention is usually 0.1 to 50% by weight, preferably 0.1 to 30% by weight, from the viewpoint of appropriately adjusting the viscosity of the composition. . Moreover, 1 type may be used for lubricating base oil, and 2 or more types may be used together.

<Other ingredients>
In the grease composition of the present invention, as in the case of the lubricant composition of the present invention, liquid crystal compounds, extreme pressure agents, alignment adsorbents, antiwear agents, wear control agents, oily agents are used within the range not impairing the effects of the present invention Add other additives such as antioxidants, viscosity index improvers, pour point depressants, cleaning dispersants, metal deactivators, corrosion inhibitors, rust inhibitors, antifoaming agents, solid lubricants, etc. Can do. Among these, 1 type may be used and 2 or more types may be used together.

<Preparation method of grease composition>
The grease composition of the present invention can be prepared by mixing the liquid crystal compound 1 described above, a lubricating base oil, and other components as required, by a conventionally known method. An example of a method for preparing the grease composition of the present invention is as follows.

  The grease composition of the present invention is obtained by mixing the components of the grease composition by a conventional method and then performing roll milling, defoaming treatment, filtering treatment, or the like as necessary. Alternatively, the grease composition can also be prepared by first mixing the oil component of the grease composition, then adding and mixing other components such as additives, and performing the above defoaming treatment as necessary. can do.

<Application of grease composition>
The grease composition of the present invention includes the liquid crystal compound 1 and the lubricating base oil described above, and may optionally include various other components. The liquid crystal compound 1 itself has lubricating performance and low evaporation loss, and as described above, has an action of reducing evaporation loss of the lubricating base oil which is a coexisting component. For this reason, the grease composition of the present invention has a low evaporation loss as a whole, and can be used in various environments such as high temperature and low pressure.

  Furthermore, although the liquid crystal compound 1 has a relatively high viscosity, the viscosity of the entire grease composition can be adjusted by the coexisting lubricating base oil. Further, the viscosity can be adjusted with a high degree of freedom by selecting the blending amount of the lubricating base oil, other components, and the type of the liquid crystal compound 1.

  As described above, the grease composition of the present invention can adjust the viscosity with a high degree of freedom and has a low evaporation loss, so that it can be suitably used as a lubricant in various mechanical devices. As in the case of the lubricant composition of the present invention, the mechanical device generally has a plurality of mechanical elements that are in contact with each other and relatively move.

  The machine elements are elements (parts, etc.) constituting various machine devices, including those that have been conventionally lubricated with a lubricant and those that may be lubricated with a lubricant in the future. .

  Examples of mechanical devices having such various machine elements include transportation machines, processing machines, computer-related equipment, office-related equipment such as copiers, and household products. The grease composition of the present invention includes For example, it can be suitably used for lubrication of bearings of these various mechanical devices.

  Specific examples of the bearings include bearings used in electrical equipment for automobiles such as electric fan motors and wiper motors; rolling bearings used in automobile engine accessories such as water pumps and electromagnetic clutch devices, and drive systems; industrial machinery Rolling bearings used in rotating devices such as small to large general-purpose motors for machines; high-speed and high-precision rotating bearings such as spindles for machine tools, motors and rotating devices for household appliances such as air conditioner fan motors and washing machines Rolling bearings used; rolling bearings used in rotating parts of computer-related equipment such as HDD devices and DVD devices; rolling bearings used in rotating parts of office machines such as copying machines and automatic ticket gates; and trains and Axle bearings for freight cars.

  Further, the grease composition of the present invention is suitable for lubricating resin pulleys used in automobile CVJ devices and electronic / electric control power steering devices, as well as lubricating mechanical elements of various rolling devices such as linear guides and ball screws. Can be used.

  The grease composition of the present invention includes, for example, engine oil, gear oil, automotive hydraulic oil, marine / aircraft lubricating oil, machine oil, turbine oil, hydraulic hydraulic oil, spindle oil, compressor oil / vacuum for vehicles such as automobiles. Pump oil, refrigerating machine oil, lubricant for metal processing, hinge oil, sewing machine oil and sliding surface oil, and lubricant for platters of HDD devices (vertical using the horizontal magnetic recording method and thermal assist recording technology) It can also be used for magnetic recording medium lubricants, micromachine lubricants, artificial bone lubricants, etc., including those used in magnetic recording systems.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these.

<Synthesis Example 1>
According to the reaction scheme shown below, the lubricating base oil compound 1 used in the following examples was synthesized.

  200 ml of ethanol was put into a 500 ml three-necked flask, and 4.7 g (0.20 mol) of metallic sodium was dissolved. To this was added 25.0 g (0.19 mol) of the compound of formula (i) dissolved in 100 ml of ethanol, and ethanol was removed under reduced pressure using an evaporator. 200 ml of DMF was added to the residue and dissolved by heating under a nitrogen atmosphere. Then, it stirred at 70 degreeC under nitrogen atmosphere for 24 hours.

  After stirring, 45.2 g (0.20 mol) of the compound of the formula (ii) was added dropwise and reacted at 70 ° C. for 24 hours.

  After the reaction, the reaction solution was poured into cold dilute hydrochloric acid (ice 30 g + distilled water 200 ml + hydrochloric acid 30 ml), and the target product was extracted with 300 ml diethyl ether using a 1 L separatory funnel. An ether layer was obtained, and 300 ml of distilled water was added to the ether layer and shaken well to obtain an ether layer by liquid separation. Anhydrous sodium sulfate was added thereto and dehydrated overnight.

  Anhydrous sodium sulfate was removed by filtration, and diethyl ether was removed under reduced pressure. The residue was distilled under reduced pressure to obtain 37.3 g (0.14 mol) of the target compound of the formula (iii).

  200 ml of diethyl ether, 20.0 (0.073 mol) of the compound of the formula (iii) and 5.8 g (0.074 mol) of pyridine are added to a 500 ml three-necked flask, and the compound of the formula (iv) 15. 0 g (0.073 mol) was added dropwise. After the dropwise addition, the mixture was refluxed at 50 ° C. for 24 hours using an oil bath.

  After refluxing, 300 ml of diethyl ether was added to the reaction solution, poured into cold dilute hydrochloric acid (ice 30 g + distilled water 200 ml + hydrochloric acid 30 ml), and extracted using a 1 L separatory funnel. An ether layer was obtained, 100 ml of distilled water was added thereto and shaken and washed well, and an ether layer was obtained by liquid separation. Anhydrous sodium sulfate was added thereto and dehydrated overnight.

  Anhydrous sodium sulfate was removed and diethyl ether was removed under reduced pressure. The residue was distilled under reduced pressure to obtain 24.7 g (0.056 mol) of the target compound of the formula (v) (lubricating base oil compound 1).

<Synthesis Example 2>
A mixture of the following three liquid crystal compounds was prepared according to Synthesis Scheme 1 and Synthesis Scheme 2 below.

(Synthesis of Compound of Formula (A-iii))
Ethanol 400 ml was put into a 1000 ml eggplant type flask, and 13.8 g (0.6 mol) of metallic sodium was dissolved. To this, 71.0 g (0.6 mol) of the compound of the formula (Ai) was added, and ethanol was removed under reduced pressure using an evaporator.

  200 ml of DMF was added to the residue, and the mixture was stirred at 70 ° C. for 24 hours under a nitrogen atmosphere. Thereafter, 73.8 g (0.6 mol) of 1-bromopropane was added and reacted at 70 ° C. for 24 hours in a nitrogen atmosphere.

  The reaction mixture was poured into 600 ml of 10% cold dilute hydrochloric acid, and the target product was extracted with 600 ml of diethyl ether using a 2 L separatory funnel. An ether layer was obtained, and 600 ml of distilled water was added thereto and washed well by shaking. An ether layer was obtained by liquid separation. Anhydrous sodium sulfate was added thereto and dehydrated overnight. Anhydrous sodium sulfate was removed, and diethyl ether was removed under reduced pressure using an evaporator. The residue was distilled under reduced pressure to obtain 24.0 g (0.15 mol) of the compound of formula (A-ii) which was a colorless and transparent liquid.

  In a 100 ml three-necked flask, 22.4 g (0.14 mol) of the compound of the formula (A-ii) and 1.0 g (0.013 mol) of pyridine were added. A solution prepared by dissolving 36.6 g (0.14 mol) of phosphorus tribromide in 20 ml of toluene was added dropwise to the reaction solution through a dropping funnel while cooling the reaction solution in an ice bath so as to keep the reaction solution at 5 ° C. or lower. After completion of dropping, the mixture was stirred at room temperature for 12 hours under a nitrogen atmosphere.

  The reaction solution was poured into 300 ml of ice water, and the target product was extracted with 300 ml of diethyl ether. An ether layer was obtained, and 300 ml of distilled water was added to the ether layer and shaken well to obtain an ether layer by liquid separation. Anhydrous sodium sulfate was added thereto and dehydrated overnight. Anhydrous sodium sulfate was removed, and diethyl ether was removed under reduced pressure using an evaporator. The residue was distilled under reduced pressure to obtain 26.7 g (0.12 mol) of a compound of formula (A-iii) which was a colorless and transparent liquid.

(Synthesis of Compound of Formula (A-v))
Ethanol 400 ml was put into a 1000 ml eggplant type flask, and 13.8 g (0.6 mol) of metallic sodium was dissolved. To this, 71.0 g (0.6 mol) of the compound of the formula (Ai) was added, and ethanol was removed under reduced pressure using an evaporator.

  200 ml of DMF was added to the residue, and the mixture was stirred at 70 ° C. for 24 hours under a nitrogen atmosphere. Thereafter, 99.0 g (0.6 mol) of 1-bromohexane was added and reacted at 70 ° C. for 24 hours in a nitrogen atmosphere.

  The reaction solution was poured into 600 ml of 10% cold dilute hydrochloric acid, and the target product was extracted with 600 ml of diethyl ether using a 2 L separatory funnel. An ether layer was obtained, and 600 ml of distilled water was added thereto and washed well by shaking. An ether layer was obtained by liquid separation. Anhydrous sodium sulfate was added thereto and dehydrated overnight. Anhydrous sodium sulfate was removed, and diethyl ether was removed under reduced pressure using an evaporator. The residue was distilled under reduced pressure to obtain 31.9 g (0.16 mol) of a compound of formula (A-iv) which was a colorless and transparent liquid.

  28.3 g (0.14 mol) of the compound of the formula (A-iv) and 1.0 g (0.013 mol) of pyridine were placed in a 100 ml three-necked flask. A solution prepared by dissolving 36.6 g (0.14 mol) of phosphorus tribromide in 20 ml of toluene was added dropwise to the reaction solution through a dropping funnel while cooling the reaction solution in an ice bath so as to keep the reaction solution at 5 ° C. or lower. After completion of dropping, the mixture was stirred at room temperature for 12 hours under a nitrogen atmosphere.

  The reaction solution was poured into 300 ml of ice water, and the target product was extracted with 300 ml of diethyl ether. An ether layer was obtained, and 300 ml of distilled water was added to the ether layer and shaken well to obtain an ether layer by liquid separation. Anhydrous sodium sulfate was added thereto and dehydrated overnight. Anhydrous sodium sulfate was removed, and diethyl ether was removed under reduced pressure using an evaporator. The residue was distilled under reduced pressure to obtain 31.1 g (0.12 mol) of a compound of formula (A-v) which was a colorless and transparent liquid.

  To a 100 ml three-necked flask, 8.9 g (0.048 mol) of 4,4′-biphenol, 20.0 g (0.145 mol) of potassium carbonate, and 70 ml of DMF were added and stirred at room temperature for 1 hour. Further, 10.7 g (0.048 mol) of the compound of the formula (A-iii) and 12.7 g (0.048 mol) of the compound of the formula (Av) were added and stirred at 80 ° C. for 24 hours. The reaction solution was poured into 300 ml of 10% cold dilute hydrochloric acid, and the target product was extracted with 300 ml of diethyl ether using a 1 L separatory funnel. An ether layer was obtained, and 300 ml of distilled water was added to the ether layer and shaken well to obtain an ether layer by liquid separation. Anhydrous sodium sulfate was added thereto and dehydrated overnight.

  Anhydrous sodium sulfate was removed by filtration, and diethyl ether was removed under reduced pressure by an evaporator. 80 ml of hexane was added to the residue, heated to 60 ° C., and purified by silica gel column chromatography. Hexane was removed under reduced pressure using an evaporator to obtain 16.5 g of a mixture of the liquid crystal compound of formula (A1), the liquid crystal compound of formula (A2) and the liquid crystal compound of formula (A3) (hereinafter “liquid crystal mixture”).

[Example (Examination of evaporation loss of lubricant)]
Lubricating base oil compound 1, lubricating base oil compound 1: liquid crystal mixture = 2: The lubricant composition of the present invention mixed at a weight ratio of 2: 1 and a comparative mixture (lubricating base oil compound 1: “4-methyl- Three pieces each having 1.000 g of 4′-ethylbiphenyl ”= 2: 1 (weight ratio) in a stainless steel container were prepared. They were placed in a constant temperature bath (normal pressure) at 100 ° C., taken out for a predetermined time, weighed with an electronic balance, and the average value of the reduced weight (evaporation loss) was plotted on a graph. The results are shown in FIG.

  From FIG. 1, it can be seen that the lubricating base oil compound 1 evaporates and loses weight in an environment of 100 ° C. and normal pressure. In a comparative mixture in which one third of the mixture was replaced with 4-methyl-4′-ethylbiphenyl, 4-methyl-4′-ethylbiphenyl was less likely to evaporate than the lubricating base oil compound 1, and the evaporation loss Slightly reduced.

  On the other hand, in the lubricant composition of the present invention, it can be seen that although two-thirds of the lubricant composition is composed of the lubricating base oil compound 1, the evaporation loss is greatly reduced. A slight evaporation loss is observed until about 100 hours, but no substantial evaporation loss is observed thereafter. This is thought to be because the ratio of the liquid crystal mixture to the lubricating base oil compound 1 is increased due to the evaporation of the lubricating base oil compound 1, thereby increasing the effect of reducing the evaporation loss.

Claims (8)

Lubricant composition comprising a lubricating base oil and a liquid crystal compound represented by the following general formula (1):

[Where:
The group A and the group B are the same or different and may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and may have a branched alkyl group having 1 to 20 carbon atoms; a fluorine atom, a hydroxyl group or An alkenyl group having 2 to 20 carbon atoms which may be substituted with a cyano group and which may have a branch; a carbon which may be substituted with a fluorine atom, a hydroxyl group or a cyano group and which may have a branch An alkynyl group of 2 to 20; or a monovalent organic residue represented by the following general formula (2):

(In the formula, R ¹¹ is optionally substituted with a fluorine atom, a hydroxyl group or a cyano group, and may have a branched alkyl group having 1 to 20 carbon atoms; substituted with a fluorine atom, a hydroxyl group or a cyano group. An alkenyl group having 2 to 20 carbon atoms which may be branched or optionally branched; alternatively, it may be substituted with a fluorine atom, a hydroxyl group or a cyano group and may have a branched carbon number 2 -20 alkynyl groups,
R ¹² and R ¹⁵ are each independently a hydrogen atom; a fluorine atom, a hydroxyl group or a cyano group, which may be substituted and optionally branched, an alkyl group having 1 to 20 carbon atoms; a fluorine atom, a hydroxyl group Or an alkenyl group having 2 to 20 carbon atoms which may be substituted with a cyano group and which may have a branch; or a branch which may be substituted with a fluorine atom, a hydroxyl group or a cyano group Or an alkynyl group having 2 to 20 carbon atoms,
R ¹³ represents a single bond; a C 1-20 alkylene group which may be substituted with a fluorine atom, a hydroxyl group or a cyano group; or a fluorine atom, a hydroxyl group or a cyano group; An alkenylene group having 2 to 20 carbon atoms which may be substituted or branched;
R ¹⁴ and R ¹⁶ are each independently an alkylene group having 1 to 20 carbon atoms which may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and may be branched; or a fluorine atom, a hydroxyl group or It is a C2-C20 alkenylene group which may be substituted with a cyano group and may have a branch. )
The group W is a divalent group selected from the group consisting of a divalent tetralin group which may be substituted, a divalent polycyclic aromatic group which may be substituted, and a group represented by the following general formula (I). Is a mesogenic group of:

(Wherein, ring D, ring E and ring F are each independently a benzene ring, cyclohexane ring, cyclohexene ring, pyridine ring, pyrimidine ring, dioxane ring, tetralin ring or polycyclic aromatic ring,
Y is independently hydrogen atom, deuterium atom, alkyl group having 1 to 8 carbon atoms, alkoxy group, alkenyl group, alkenyloxy group, alkynyl group, alkynyloxy group, alkoxyalkyl group, alkanoyloxy group, alkoxycarbonyl. A group, a halogen atom, or a cyano group,
s1 to s3 are each independently an integer up to 1, or the number of sites to which a substituent of ring D, ring E or ring F can be bonded;
when s1 to s3 are 2 or more, a plurality of Y bonded to the same ring may be the same or different;
Z ₁ and _{Z 2} are each independently a single _{bond, -CO-O -, - O} -CO -, - CH 2 O -, - OCH 2 -, - CH 2 CH 2 -, - CH = CHCH 2 O-, _{-CH = CH -, - CF 2} O -, - OCF 2 -, - S -, - SO -, - SO 2 - or a -C≡C-,
r is 0, 1 or 2;
When r is 2, two Z ₁ may be the same or different, and the two rings D may be the same or different, and are bonded to the two rings D, respectively. Y may be the same or different. ]].   In the general formula (1), the group A and the group B are the same or different and may be substituted with a fluorine atom, a hydroxyl group or a cyano group and may have a branched alkyl group having 1 to 20 carbon atoms. The lubricant composition according to claim 1, which is a group or an organic residue represented by the general formula (2). In the general formula (2), R ¹¹ is an alkyl group having 1 to 20 carbon atoms which may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and may have a branch;
R ¹² and R ¹⁵ are each independently a hydrogen atom; or a C 1-20 alkyl group which may be substituted with a fluorine atom, a hydroxyl group or a cyano group, and which may have a branch;
R ¹³ , R ¹⁴ and R ¹⁶ are each independently an alkylene group having 1 to 20 carbon atoms which may be substituted with a fluorine atom, a hydroxyl group or a cyano group and which may have a branch. Or 3. The lubricant composition according to 2. In the general formula (I), ring D, ring E and ring F each independently represent a benzene ring, cyclohexane ring, dioxane ring, tetralin ring or polycyclic aromatic ring, and Y each independently represents a hydrogen atom or halogen. The lubricant composition according to claim 1, wherein the lubricant composition represents an atom, Z ₁ and Z ₂ each independently represent a single bond or —CO—O—, and r represents 0 or 1. The lubricant composition according to any one of claims 1 to 4, wherein, in the general formula (2), R ¹⁴ and R ¹⁶ are the same group.   The lubricant composition according to any one of claims 1 to 5, wherein the content of the liquid crystal compound represented by the general formula (1) in the lubricant composition is 5% by weight or more.   A liquid crystal grease comprising the lubricant composition according to claim 1.   The lubricant composition according to any one of claims 1 to 6 or the liquid crystal according to claim 7, wherein the lubricant composition is disposed on at least a part of a contact surface of the mechanical elements in contact with each other and relatively moved. A mechanical device having grease.