Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Heterocyclic ring compound; a heterocyclic ring is one...
Reexamination Certificate
2001-06-15
2003-03-04
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Heterocyclic ring compound; a heterocyclic ring is one...
C508S243000, C508S257000
Reexamination Certificate
active
06528460
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of priority under 35 U.S.C. § 119 to Japanese Application No. 2000-180303, filed Jun. 15, 2000, and Japanese Application No. 2001-173450, filed Jun. 8, 2001, the entire contents of which applications being incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lubricant composition which can be supplied to a mechanical friction sliding member, and more particularly to a lubricant composition which is excellent in wear resistance, extreme pressure properties and low friction properties.
2. Description of the Related Art
The use of a liquid-crystalline compound or the like as a lubricant oil or composition has been studied. For example, International Patent Publication No. WO503326/1990 proposes use of a liquid crystal as a lubricant composition as a fluid organic material for a machine member working under varying frictional conditions, where transformation of the liquid crystal between the thermotropic and isotropic phases is utilized. Japanese Patent Publication No. 21436/1990 proposes a chronometer oil mainly composed of a liquid crystal or mixture of liquid crystals, in particular nematic liquid crystal. Japanese Laid-Open Patent Application No.82582/1995 proposes a lubricant composition containing a liquid crystal compound and fluorine-based oil, and Japanese Laid-Open Patent Application No.279973/1998 proposes a lubricant containing a liquid-crystalline compound of sulfur-containing phthalocyanine or metal complex.
In spite of these proposals, however, the techniques are not yet sufficiently developed for use of a single body of liquid-crystalline compound or the like as a lubricant or dissolving a liquid-crystalline compound in a lubricant base oil, in order to produce a lubricant oil or composition containing a practical liquid-crystalline compound or the like, sufficiently excellent in wear resistance, extreme pressure properties and low friction properties. Recently, machine sliding members, in particular, have been required to work at higher temperatures, at higher or lower speeds, and/or at higher loads, as well as becoming smaller and/or lighter. Accordingly, the lubricating conditions for these members are also becoming more severe, needing more practical lubricant of higher wear resistance, extreme pressure properties and low friction properties.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a practical lubricant composition excellent in wear resistance, extreme pressure properties and low friction properties, for example, for mechanical friction sliding members.
The inventors of the present invention have found, after having extensively studied to solve the problems associated with the above-described conventional techniques, that a compound having a specific structure exhibits excellent properties, in particular low friction coefficient, under severe lubricating conditions, i.e., boundary lubrication or mixed lubrication conditions, reaching the present invention.
According to a first aspect of the invention, provided is a lubricant composition comprising, as a major ingredient, a compound of formula (1):
(R—X—)
m
—D (1)
wherein D is a heterocyclic residue of a 5- to 7-membered cyclic structure positioned at the center of the molecule, or a compound residue of cyclic structure with m radiating side chains; X is a single bond, a group represented by NR
1
(wherein R
1
is an alkyl group having a carbon number of 1 to 30 or a hydrogen atom), an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or a combination thereof forming a divalent coupling group; R is an alkyl, alkenyl, alkynyl, aryl or heterocyclic group; and m is an integer from 3 to 11.
In the lubricant composition, each of at least 3 of the m R groups preferably contains a substituent containing a straight or branched alkyl chain having a total carbon number of 8 or more, a straight or branched oligoalkyleneoxy chain having a total carbon number of 4 or more, a straight or branched polyalkyl fluoride chain having a total carbon number of 2 or more, a straight or branched polyalkyl fluoride ether chain having a total carbon number of 2 or more, or a straight or branched organopolysilyl chain.
The formula (1) can be a triazine, preferably represented by formula (2), i.e., D in formula (1) is a 1,3,5-trisubstituted triazine ring:
wherein, X
1
, X
2
and X
3
are each a single bond, a group represented by NR
1
(wherein R
1
is an alkyl group having a carbon number of 1 to 30 or a hydrogen atom), an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or a combination thereof forming a divalent coupling group; and R
11
, R
12
and R
13
are each an alkyl, alkenyl, alkinyl, aryl or heterocyclic group. Each of X
1
, X
2
and X
3
in formula (2) is preferably an imino group (—NH—).
The composition can contain one or more additives selected from the group consisting of antiwear agents, extreme pressure agents, antioxidants, viscosity index improvers, detergent-dispersants, metal deactivators, corrosion inhibitors, rust inhibitors, antifoamants and combinations thereof.
The composition preferably is composed of a base oil comprising 0.1 to 20% by weight, based on the base oil, of the compound of formula (1), and 80 to 99.9% by weight, based on the base oil, of a mineral and/or synthetic oil.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
1. The Compound of Formula (1)
The compound used as the major ingredient for the lubricant composition of the present invention is a heterocyclic compound shown by the chemical formula (1):
(R—X—)
m
—D (1)
wherein D is a heterocyclic residue of a 5- to 7-membered cyclic structure positioned at the center of the molecule, or a compound residue of cyclic structure with m radiating side chains; X is a single bond, a group represented by NR
1
(wherein R
1
is an alkyl group having a carbon number of 1 to 30 or a hydrogen atom), an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or a combination thereof forming a divalent coupling group; R is an alkyl, alkenyl, alkynyl, aryl or heterocyclic group; and m is an integer from 3 to 11.
D in the chemical formula (1) can be a heterocyclic residue of 5- to 7-membered cyclic structure positioned at the center of the molecule, preferably 5- or 6-membered, more preferably 6-membered. Examples of these skeletons are described in Iwanami Rikagaku Jiten, third edition (revised and enlarged), published by Iwanami Shoten, Appendix Chapter 11, Nomenclature of Organic Chemistry, Table 4: Names of Main Heterocyclic Compounds, pp.1606. The heterocyclic rings preferably show aromaticity.
When X in the chemical formula (1) is a single bond, it may be directly bonded by a nitrogen atom with free valence, such as that in a heterocyclic group (e.g., piperidine group). Moreover, it may be bonded by a hetero atom having no free valence, to form an onium salt, e.g., oxysonium, sulfonium or ammonium salt. X in the chemical formula (1) is preferably a sulfur atom or a group represented by the formula NR
1
, wherein R
1
is preferably an alkyl group having a carbon number of 3 or less, or a hydrogen atom. A carbamoyl, sulfamoyl, carboxyl, sulfo, hydroxyamino group or the like may be also used.
When R in the chemical formula (1) is an alkyl group, it has a carbon number of 1 to 30, preferably 2 to 30, more preferably 4 to 30, still more preferably 6 to 30. The alkyl group may be of straight chain or branched. It may have a substituent. The substituents include, for example, a halogen atom, an alkoxy group (e.g., methoxy, ethoxy, methoxyethoxy or phenoxy), a sulfide group (e.g., methylthio, ethylthio or propylthio), an alkyl amino group (e.g., methylamino or propylamino), an acyl group (e.g., acetyl, propanoyl, octanoyl or benzoyl) and an acyloxy group (e.g., acetoxy, pivaloyloxy or benzoyloxy), and a hydroxyl, mercapto, amino, carboxyl, sulfo, carbamoyl, sulfamoyl or ureide group.
When R in the chemical formula
Fuwa Yoshio
Iisaka Hirofumi
Kawata Ken
Miyata Hitoshi
Ueda Fumio
Burns Doane , Swecker, Mathis LLP
Fuji Photo Film Co. , Ltd.
McAvoy Ellen M.
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