Grease composition, viscous agent, and mechanical element

Abstract

A grease composition comprising at least one polymer having a mesogen structure in the principal chain or in the side chain(s) thereof, and at least one viscous agent is disclosed. A viscous agent which is a discotic compound having, in the molecule thereof, a discotic core and three or more side chain groups radially extended from said discotic core is also disclosed. The discotic core and/or said side chain groups has at least one tautomeric group therein, and at least one side chain group of said three or more side chains has, at the end portion thereof, a long chain group in which 20 or more atoms selected from the group consisting of oxygen, carbon, nitrogen, silicon and sulfur atoms are linked in a straight-chain-like manner or in a branched manner.

1 . A grease composition comprising at least one polymer having a mesogen structure in the principal chain or in the side chain(s) thereof, and one viscous agent. 
     
     
         2 . The grease composition of  claim 1 , wherein said mesogen structure has a discotic form. 
     
     
         3 . The grease composition of  claim 1 , wherein said at least one polymer is a polymer having a mesogen structure in the side chain(s) thereof. 
     
     
         4 . The grease composition of  claim 3 , wherein said at least one polymer is a polymer comprising at least a repeating unit represented by the formula (1-1) below: 
       
         
           
           
               
               
           
         
         where in the formula (1-1), “Chain” is a repeating unit derived from a monomer composing the principal chain having at least L as a substituent; D represents a cyclic mesogen group; each R 0  represents a substituent, k is an integer of 0 or larger and not larger than the maximum number of R 0  substitutable on the cyclic mesogen group, k (R 0 )s may be same with or different from each other; L independently represents a divalent linking group; wherein at least one of R 0  and L has a C 5  or longer alkylene chain, oligoalkyleneoxy chain, oligosiloxy chain or oligoperfluoroalkyleneoxy chain therein. 
       
     
     
         5 . The grease composition of  claim 3 , wherein said at least one polymer comprises at least a repeating unit represented by the formula (1-2) below: 
       
         
           
           
               
               
           
         
         wherein in the formula (1-2), “Chain” is a repeating unit derived from a monomer composing the principal chain having at least L as a substituent; each X independently represents N(R 1 ), S, or O, which may be same with or different from each other; R 1  represents a hydrogen atom or alkyl group; each R 2  represents a substituent, which may be same with or different from each other; m represents an integer from 0 to 4 and n represents an integer from an integer 0 to 5, wherein a plurality of (n)s in the formula may be same with or different from each other; each L represents a divalent linking group; wherein at least one of R 2  and L has a C 5  or longer alkylene chain, oligoalkyleneoxy chain, oligosiloxy chain or oligoperfluoroalkyleneoxy chain therein. 
       
     
     
         6 . The grease composition of  claim 3 , wherein said at least one polymer is a polymer comprising at least a repeating unit represented by the formula (1-3) below: 
       
         
           
           
               
               
           
         
         where in the formula (1-3), “Chain” is a repeating unit derived from a monomer composing the principal chain having at least L as a substituent; each R 3  represents a substituent, which may be same with or different from each other; m′ represents an integer from 0 to 3 and n′ represents an integer from 0 to 4, a plurality of (n′)s in the formula may be same with or different from each other; L represents a divalent linking group; wherein at least one of R 3  and L has a C 5  or longer alkylene chain, oligoalkyleneoxy chain, oligosiloxy chain or oligoperfluoroalkyleneoxy chain therein. 
       
     
     
         7 . The grease composition of  claim 3 , wherein D in the formula (1-1) is a cyclic mesogen group represented by any of the formulae [a] to [h] below: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         where, each * in the formula means a site bindable with L and/or R 0 . 
       
     
     
         8 . The grease composition of  claim 1 , wherein said at least one polymer is a polymer having a mesogen structure in the principal chain thereof. 
     
     
         9 . The grease composition of  claim 8 , wherein said at least one polymer is a polymer comprising a repeating unit represented by the formula (2-1) below: 
       
         
           
           
               
               
           
         
         where in the formula (2-1), D represents a cyclic mesogen group, each R 0  independently represents a substituent, k is an integer of 0 or larger and not larger than the maximum number of R 0  substitutable on the cyclic mesogen group, k (R 0 )s may be same with or different from each other; each L independently represents a divalent linking group; wherein at least one of R 0  and L has a C 5  or longer alkylene chain, oligoalkyleneoxy chain, oligosiloxy chain or oligoperfluoroalkyleneoxy chain therein. 
       
     
     
         10 . The grease composition of  claim 8 , wherein said at least one polymer comprises a repeating unit represented by the formula (2-2a) or (2-2b) below: 
       
         
           
           
               
               
           
         
         where in the formulae (2-2a) and (2-2b), each X independently represents N (R 1 ), S or O, which may be same with or different from each other; R 1  independently represents a hydrogen atom or alkyl group; each R 2  represents a substituent, which may be same with or different from each other; 1 represents an integer from 0 to 3, m represents an integer from 0 to 4, and n represents an integer from 0 to 5, a plurality of (m)s and (n)s in the formulae may be same with or different from each other; each L independently represents a divalent linking group, which may be same with or different from each other; wherein at least one of R 2  and L has a C 5  or longer alkylene chain, oligoalkyleneoxy chain, oligosiloxy chain or oligoperfluoroalkyleneoxy chain. 
       
     
     
         11 . The grease composition of  claim 8 , wherein said at least one polymer comprises a repeating unit represented by the formula (2-3a) or (2-3b) below: 
       
         
           
           
               
               
           
         
         where in the formulae (2-3a) and (2-3b), each R 3  represents a substituent, which may be same with or different from each other; l′ represents an integer from 0 to 2, m′ represents an integer from 0 to 3, and n′ represents an integer from 0 to 4, a plurality of (m′)s and (n′)s in the formulae may be same with or different from each other; each L independently represents a divalent linking group; wherein at least one of R 3  and L has a C 5  or longer alkylene chain, oligoalkyleneoxy chain, oligosiloxy chain or oligoperfluoroalkyleneoxy chain therein. 
       
     
     
         12 . The grease composition of  claim 8 , wherein said at least one polymer comprises a repeating unit represented by the formula (2-4) below: 
       
         
           
           
               
               
           
         
         where in the formula (2-4), each R 4  represents a substituent, which may be same with or different from each other; n″ represents an integer from 0 to 4, which may be same with or different from each other; L represents a divalent linking group; wherein at least one of R 4  and L has a C 5  or longer alkylene chain, oligoalkyleneoxy chain, oligosiloxy chain or oligoperfluoroalkyleneoxy chain therein. 
       
     
     
         13 . The grease composition of  claim 8 , wherein D in the formula (2-1) is a cyclic mesogen group represented by any one of the formulae [a] to [h] below: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         where, * means a site bindable with L and/or R 0 . 
       
     
     
         14 . The grease composition of  claim 1 , wherein said at least one polymer has a weight-average molecular weight of 5,000 to 200,000. 
     
     
         15 . The grease composition of  claim 1 , wherein said at least one polymer is a polyester-base polymer comprising repeating units condensed by ester bonds. 
     
     
         16 . The grease composition of  claim 1 , comprising said at least one polymer in an amount of 0.1 to 30% by mass with respect to the total mass. 
     
     
         17 . The grease composition of  claim 1 , comprising said at least one polymer in a form of dispersed particles having a mean particle size of 10 nm to 10 μm. 
     
     
         18 . The grease composition of  claim 1 , further comprising at least one species of polymer different from said at least one polymer. 
     
     
         19 . The grease composition of  claim 1 , further comprising at least one species of compound represented by the formulae (4)—a, b, c, d, e, f and g below: 
       
         
           
           
               
               
           
         
         where in the formulae, each R 4  represents a substituted alkyl group, phenyl group or heterocyclic group, and these may be substituted by at least one substituent comprising a divalent C 8  or longer alkylene group, oligoalkyleneoxy chain, oligosiloxy chain, oligoperfluoroalkyleneoxy chain or disulfide group. 
       
     
     
         20 . The grease composition of  claim 1 , wherein said at least one polymer has in the side chain(s) thereof an organopolysiloxane group represented by the formula (6) below: 
       
         
           
           
               
               
           
         
         where in the formula (6), each R independently represents a substituted or non-substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, which may be same with or different from each other; each R 1  independently represents an alkyl group having 1 to 6 carbon atoms, which may be same with or different from each other; x represents an integer from 5 to 120, and y represents 0 or 1. 
       
     
     
         21 . The grease composition of  claim 1 , wherein said at least one polymer has, in the side chain(s) thereof, a polyfluoroalkyl group or polyfluoroalkylether group represented by the formula (7) below: 
       
         
           
           
               
               
           
         
         wherein the formula (7), Rf represents a perfluoroalkyl group having 1 to 15 carbon atoms, each of m, n, p and q represents 0 or an integer of 1 or larger, m+n+p+q is 2 to 200; r is 0 or 1, r=0 gives s=1 and Rf represents a perfluoroalkyl group having 12 or more carbon atoms, and s represents 0 or 1 if r=1. 
       
     
     
         22 . The grease composition of  claim 3 , wherein said at least one polymer has ester bonds in the side chain(s) thereof. 
     
     
         23 . The grease composition of  claim 3 , wherein said at least one polymer has, in the side chain(s) thereof, a divalent group represented by the formula (8) below:
   (C 2 H 4 O) n —  (8)   where in the formula (8), n represents an integer of 2 or larger.   
     
     
         24 . The grease composition of  claim 8 , wherein said at least one polymer has, in the principal chain and/or side chain(s) thereof, an ester bond. 
     
     
         25 . The grease composition of  claim 8 , wherein said at least one polymer has, in the principal chain and/or side chain(s) thereof, a divalent group represented by the formula (8) below:
   —(C 2 H 4 O) n —  (8)   where in the formula, n represents an integer of 2 or larger.   
     
     
         26 . The grease composition of  claim 8 , wherein said at least one polymer has, in the principal chain thereof, a ureylene group obtained by addition polymerization of a compound having a mesogen group and a bifunctional isocyanate with diamine, or addition polymerization of a compound having a mesogen group and a bifunctional amino group with diisocyanate. 
     
     
         27 . The grease composition of  claim 1 , further comprising a base oil. 
     
     
         28 . The grease composition of  claim 27 , comprising said base oil in an amount of 0 to 99.9% by mass with respect to the total mass. 
     
     
         29 . The grease composition of  claim 27 , comprising at least one species of silicone oil as said base oil. 
     
     
         30 . The grease composition of  claim 27 , comprising at least one species of polyfluoroalkyl ether oil as said base oil. 
     
     
         31 . The grease composition of  claim 27 , comprising at least one species of diphenyl ether oil represented by the formula (9) or formula (10) as said base oil: 
       
         
           
           
               
               
           
         
         where in the formula (9), R 2  and R 3  independently represent a straight-chain-like or branched perfluoroalkyl group or partially substituted compound thereof, having 1 to 25 carbon atoms, and ratio of the number of atoms of fluorine/carbon of R 2 , R 3  is 0.6 to 3, 
       
       
         
           
           
               
               
           
         
         where in the formula (10), one of R 4 , R 5  and R 6  represents a hydrogen atom, and the others independently represent straight-chain-like or branched alkyl groups, having 1 to 26 carbon atoms. 
       
     
     
         32 . The grease composition of  claim 27 , comprising at least one species of aromatic ester oil having at least three side chains each containing a carboester group, as said base oil. 
     
     
         33 . The grease composition of  claim 27 , comprising at least one species of biodegradable oil as said base oil. 
     
     
         34 . The grease composition of  claim 27 , comprising, as said base oil, at least one species of aromatic ester oil of which hydrocarbon group has 6 to 15 carbon atoms. 
     
     
         35 . The grease composition of  claim 27 , wherein said base oil is at least one species selected from (A) hydrides of alpha-alkylstyrene dimer to trimer, (B) hydrides of cyclopentadiene-base condensed ring hydrocarbons mainly composed of cyclopentadiens, and a trimer to hexamer mainly composed of at least either of alpha-olefins and monovinyl aromatic hydrocarbons, having a ratio (ND/CD) of hydrogen content on the double bond of norbornene ring (ND) and hydrogen content on the double bonds of cyclopentadiene ring (CD) of 0.9 to 1.3, and (C) saturated hydrocarbon-base synthetic hydrocarbons having in the molecule thereof any cyclic structure selected from cyclohexane ring, decalin ring, bicycloheptane ring and bicyclooctane ring. 
     
     
         36 . The grease composition of  claim 1 , wherein said viscous agent is an urea-base compound, and said at least one polymer has tautomeric group(s) in the principal chain and/or side chain(s) thereof. 
     
     
         37 . The grease composition of  claim 1 , wherein said viscous agent is a lithium soap, and said at least one polymer has tautomeric group(s) in the principal chain and/or side chain(s) thereof. 
     
     
         38 . The grease composition of  claim 1 , showing worked penetration falling within the range from 205 to 395 at 40° C. 
     
     
         39 . A mechanical element comprising at least two surfaces movable at peripheral speeds different from each other, and a grease composition as set forth in  claim 1  disposed between said two surfaces. 
     
     
         40 . The mechanical element of  claim 39 , wherein at least one of said two surfaces is composed of a resin. 
     
     
         41 . The mechanical element of  claim 39 , wherein at least one of said two surfaces is composed of diamond-like carbon or ceramic. 
     
     
         42 . A grease composition comprising:
 at least one discotic compound having a discotic core, at least one viscous agent and a base oil, and showing worked penetration equal to or smaller than 480 at 40° C.   
     
     
         43 . The grease composition of  claim 42 , wherein said at least one discotic compound is a compound represented by the formula (3-1) below: 
       
         
           
           
               
               
           
         
         where in the formula, D represents a cyclic group bindable with m side chains, each X independently represents a single bond, NR 1  group (R 1  represents a hydrogen atom or alkyl group having 1 to 30 carbon atoms), oxygen atom, sulfur atom, carbonyl group, sulfonyl group, or divalent linking group composed of any combinations thereof, each R independently represents a substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, halogen atom, hydroxy group, amino group, mercapto group, cyano group, sulfide group, carboxyl group or salt thereof, sulfo group or salt thereof, hydroxyamino group, ureido group or urethane group, and m represents an integer from 2 to 11. 
       
     
     
         44 . The grease composition of  claim 43 , wherein D represents a group having 5- to 7-membered ring structure, or a residue of porphyrin or phthalocyanine. 
     
     
         45 . The grease composition of  claim 43 , wherein D is a tautomeric group represented by the formula (a) or (b) below: 
       
         
           
           
               
               
           
         
         where in the formula (a), “A” represents a ring composed of 5 to 7 atoms, wherein one of, or two or more of the ring-composing atoms may have substituent (s), or may be condensed with other ring; 
       
       
         
           
           
               
               
           
         
         where in the formula (b), “B” represents a ring composed of 5 to 7 atoms, wherein one of, or two or more of the ring-composing atoms may have substituent (s), or may be condensed with other ring. 
       
     
     
         46 . The grease composition of  claim 43 , wherein D is a group represented by the formula (c) below: 
       
         
           
           
               
               
           
         
         where in the formula (c), each Z independently represents any of oxygen atom, sulfur atom, and —NR—, which may be same with or different from each other; and R represents a hydrogen atom, or alkyl group which may be substituted. 
       
     
     
         47 . The grease composition of  claim 42 , wherein said at least one discotic compound is a compound represented by the formula (3-2) below: 
       
         
           
           
               
               
           
         
         where in the formula, each of X 1 , X 2  and X 3  independently represents a single bond, NR 1  group (R 1  represents a hydrogen atom or alkyl group having 1 to 30 carbon atoms), oxygen atom, sulfur atom, carbonyl group, sulfonyl group, or divalent linking group composed of any combinations thereof, each of R 11 , R 12  and R 13  independently represents a substituted or non-substituted alkyl group, alkenyl group, alkynyl group, aryl group, halogen atom, hydroxy group, amino group, mercapto group, cyano group, sulfide group, carboxyl group or salt thereof, sulfo group or salt thereof, hydroxyamino group, ureido group or urethane group. 
       
     
     
         48 . The grease composition of  claim 42 , wherein said at least one discotic compound is a compound represented by the formula (3-3) below: 
       
         
           
           
               
               
           
         
         where in the formula, each of X 21 , X 22  and X 23  independently represents a single bond, NR 1  group (R 1  represents a hydrogen atom or alkyl group having 1 to 30 carbon atoms), oxygen atom, sulfur atom, carbonyl group, sulfonyl group, or divalent linking group composed of any combinations thereof, each of R 21 , R 22  and R 23  independently represents a substituent, and each of a21, a22 and a23 independently represents an integer from 1 to 5. 
       
     
     
         49 . The grease composition of  claim 42 , wherein said at least one discotic compound has at least one substituent attached to said discotic core, and said at least one substituent is a tautomeric group, or has a tautomeric group as a part thereof. 
     
     
         50 . The grease composition of  claim 49 , wherein said tautomeric group is a tautomeric group represented by the formula (a) or (b), or tautomerizable ureylene group, urethane group, amide group or ureido group: 
       
         
           
           
               
               
           
         
         where in the formula (a), A is a ring composed of 5 to 7 atoms, and one of, or two or more of the ring-composing atoms may have substituent(s), or may be condensed with other ring; 
       
       
         
           
           
               
               
           
         
         where in the formula (b), B is a ring composed of 5 to 7 atoms, and one of, or two or more of the ring-composing atoms may have substituent(s), or may be condensed with other ring. 
       
     
     
         51 . The grease composition of  claim 49 , wherein said tautomeric group is a tautomerizable ureylene group. 
     
     
         52 . The grease composition of  claim 42 , wherein said at least one discotic compound has at least one substituent attached to said discotic core, and said at least one substituent has an organopolysiloxane group represented by the formula (6) below therein: 
       
         
           
           
               
               
           
         
         where in the formula (6), each R independently represents a substituted or non-substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, which may be same with or different from each other; each R 1  independently represents an alkyl group having 1 to 6 carbon atoms, which may be same with or different from each other; x represents an integer from 5 to 120, and y represents 0 or 1. 
       
     
     
         53 . The grease composition of  claim 42 , wherein said at least one discotic compound has at least one substituent attached to said discotic core, and said at least one substituent has a polyfluoroalkyl group or polyfluoroalkyl ether group represented by the formula (7) below therein: 
       
         
           
           
               
               
           
         
         where in the formula (7), each Rf represents a perfluoroalkyl group having 1 to 15 carbon atoms, each of m, n, p and q represents 0 or an integer of 1 or larger, m+n+p+q is 2 to 200; r is 0 or 1, r=0 gives s=1 and Rf represents a perfluoroalkyl group having 12 or more carbon atoms, and s represents 0 or 1 if r=1. 
       
     
     
         54 . The grease composition of  claim 42 , wherein said at least one discotic compound has at least one substituent containing an ester bond, attached to said discotic core. 
     
     
         55 . The grease composition of  claim 42 , wherein said at least one discotic compound has at least one substituent containing a divalent group represented by the formula (8) below, attached to said discotic core:
   —(C 2 H 4 O) n —  (8)   where in the formula (8), n represents an integer of 2 or larger.   
     
     
         56 . A viscous agent which is a discotic compound having, in the molecule thereof, a discotic core and three or more side chain groups radially extended from said discotic core,
 wherein said discotic core and/or said side chain groups has at least one tautomeric group therein, and   at least one side chain group of said three or more side chains has, at the end portion thereof, a long chain group in which 20 or more atoms selected from the group consisting of oxygen, carbon, nitrogen, silicon and sulfur atoms are linked in a straight-chain-like manner or in a branched manner.   
     
     
         57 . The viscous agent of  claim 56 , wherein said discotic core has at least one tautomeric group represented by the formula (a) or (b) below therein: 
       
         
           
           
               
               
           
         
         where in the formula (a), “A” represents a ring composed of 5 to 7 atoms, one of, or two or more ring-composing atoms may have substituent (s), or may be condensed with other ring, and “A” and/or ring condensed therewith comprise at least two side chain groups; 
       
       
         
           
           
               
               
           
         
         where in the formula (b), “B” represents a ring composed of 5 to 7 atoms, one of, or two or more ring-composing atoms may have substituent (s), or may be condensed with other ring, and “B” and/or ring condensed therewith comprise at least three side chain groups. 
       
     
     
         58 . The viscous agent of  claim 56 , wherein said discotic core has a group represented by the formula (c) below therein: 
       
         
           
           
               
               
           
         
         where in the formula (c), each Z independently represents an oxygen atom, sulfur atom, or —NR—, which may be same with or different from each other; and R represents a hydrogen atom, or alkyl group which may be substituted. 
       
     
     
         59 . The viscous agent of  claim 56 , wherein at least one of said three or more side chain groups has a discotic group containing at least one tautomeric group represented by the formula (a) or (b) below, or tautomerizable ureylene group, urethane group, amide group or ureido group: 
       
         
           
           
               
               
           
         
         where in the formula (a), “A” represents a ring composed of 5 to 7 atoms, one of, or two or more ring-composing atoms may have substituent (s), or may be condensed with other ring, and “A” and/or ring condensed therewith comprise at least two side chains; 
       
       
         
           
           
               
               
           
         
         where in the formula (b), “B” represents a ring composed of 5 to 7 atoms, one of, or two or more ring-composing atoms may have substituent (s), or may be condensed with other ring, and “B” and/or ring condensed therewith comprise at least three side chain groups. 
       
     
     
         60 . The viscous agent of  claim 56 , wherein at least one of said three or more side chain groups has at least one tautomerizable ureylene group. 
     
     
         61 . The viscous agent of  claim 56 , wherein said long chain group is a group having a C 13  or longer straight-chain-like or branched alkyl group or alkylene group therein. 
     
     
         62 . The viscous agent of  claim 56 , wherein said long chain group is a group having an organopolysiloxane group represented by the formula (6) below therein: 
       
         
           
           
               
               
           
         
         where in the formula (6), each R independently represents a substituted or non-substituted monovalent hydrocarbon having 1 to 18 carbon atoms, which may be same with or different from each other; each R 1  independently represents an alkyl group having 1 to 6 carbon atoms, which may be same with or different from each other; x represents an integer from 5 to 120, and y represents 0 or 1. 
       
     
     
         63 . The viscous agent of  claim 56 , wherein said long chain group has a polyfluoroalkyl group or polyfluoroalkyl ether group represented by the formula (7) below therein: 
       
         
           
           
               
               
           
         
         where in the formula (4-7), each Rf represents a perfluoroalkyl group having 1 to 15 carbon atoms; each of m, n, p and q represents 0 or an integer of 1 or larger, m+n+p+q is 2 to 200; r is 0 or 1, r=0 gives s=1 and Rf represents a perfluoroalkyl group having 12 or more carbon atoms, and s represents 0 or 1 if r=1. 
       
     
     
         64 . The viscous agent of  claim 56 , wherein the discotic compound has an ester bond between said long chain group and said discotic core. 
     
     
         65 . The viscous agent of  claim 56 , wherein the discotic compound has a divalent group represented by the formula (8) below, between said long chain group and said discotic core:
   —(C 2 H 4 O) n —  (8)   where in the formula (8), n represents an integer of 2 or larger.   
     
     
         66 . The viscous agent of  claim 56 , wherein two or more molecules of said discotic compound form a complex. 
     
     
         67 . The viscous agent of  claim 56 , wherein at least one of said three or more side chain groups is capable of forming an intra-molecular or inter-molecular hydrogen bond. 
     
     
         68 . The viscous agent of  claim 56 , wherein said discotic compound has, in the molecule thereof, two or more tautomeric groups, each of said tautomeric groups comprises at least one species selected from the group consisting of residues of melamine, isocyanric acid, uracil, barbituric acid, trimellitic acid, purine, thymine, adenine, cytocine and their residues, and is capable of forming a plurality of intra-molecular or inter-molecular hydrogen bonds. 
     
     
         69 . The viscous agent of  claim 56 , wherein said discotic compound is a polymer having said discotic core in the principal chain and/or side chain(s) thereof. 
     
     
         70 . A grease composition comprising a viscous agent as set forth in  claim 56 , showing worked penetration equal to or smaller than 480 at 40° C.