The invention is directed towards the field of lubricant compositions, in particular lubricant
compositions for transmissions or engines and particularly motor vehicle engines.
One of the objectives of lubricant compositions is to reduce phenomena of friction and
wear of mechanical parts moving in contact with one another. One particular objective of
10 lubricant compositions is to limit these friction phenomena in vehicle engines, particularly
motor vehicle engines. In addition, there is expanding use of carbon coatings in engines
particularly motor vehicle engines. It would therefore be of advantage to be able to
propose lubricant compositions allowing a reduction in friction phenomena whether for
steel/steel, carbon coating/carbon coating or steel/carbon coating contacts.
15 In general, to limit friction phenomena, friction modifiers can be integrated in lubricant
compositions. It is known in particular to add fatty amines as friction modifiers. However,
these amines may have a harmful effect on seals, particularly seals of mechanical parts
and notably fluorinated polymeric seals. These amines may effectively cause accelerated
degradation of the mechanical properties of seals.
20 It is also known to use organomolybdenum compounds to reduce friction phenomena,
more particularly for contacts between two steel surfaces. However, it is known to persons
skilled in the art that the use of organomolybdenum compounds, in particular
organomolybdenum compounds comprising a dithiocarbamate group, can cause
aggravated wear of mechanical parts. Also, it has been observed that organomolybdenum
25 compounds contained in a lubricant can degrade and even detach a carbon coating from
a surface, and that this degradation can be accentuated with increased content of
organomolybdenum compounds in the lubricant.
It would therefore be of advantage to provide lubricant compositions which, whilst
reducing friction phenomena particularly in the presence of carbon coated surfaces, have
30 a moderate impact on other engine members and on seals in particular.
Additionally, one of the objectives of lubricant compositions is improve engine yield and
hence permit fuel savings.
It is therefore one objective of the invention to provide a lubricant composition allowing a
35 reduction in friction phenomena, in particular in the presence of surfaces with a carbon
-----"-'---
2
coating, which has a limited impact on degradation of seals, in particular engine seals,
particularly of vehicle engines, for example motor vehicle engines.
It is a further objective of the present invention to provide said composition allowing a
reduction in friction phenomena whether for steel/steel, carbon coating/carbon coating or
5 steel/carbon coating contacts.
10
15
A further objective of the invention is to provide said composition also allowing a decrease
in fuel consumption.
Other objectives will become apparent on reading the following description of the
invention.
To meet these objectives and the shortcomings of known lubricant compositions, the
present invention proposes a lubricant composition comprising:
where:
at least one base oil;
at least one organomolybdenum compound;
at least one fully or partly neutralized amine salt, the amine meeting following
formula (\):
R-N(X)-Y (I)
R is a linear or branched, fully or partly saturated hydrocarbon group having 2 to 24
20 carbon atoms, preferably 4 to 24 and more preferably 14 to 24, in particular 16 to 24, for
example 18 to 24 carbon atoms;
X is a hydrogen atom, a linear or branched, fully or partly saturated hydrocarbon group
having 1 to 24 carbon atoms, preferably 1 to 10 carbon atoms, in particular 1 to 8 carbon
atoms, a benzyl group or group of formula-R1-[NH-R2
] 0-NH,;
25 Y is a hydrogen atom, a linear or branched, fully or partly saturated hydrocarbon group
having 1 to 24 carbon atoms, preferably 1 to 10 carbon atoms, in particular 1 to 8 carbon
atoms, a benzyl group or group of formula-R1-[NH-R2
] 0-NH2;
n is an integer of 0 to 3, preferably 0 to 2, preferably 0 or 1;
R1 and R2
, the same or different are a linear or branched alkyl group having 2 to 4 carbon
30 atoms, preferably 2 to 3 carbon atoms, preferably CH2CH2 or CH2CH2CH2 ;
at least one of X or Y is a hydrogen atom or -R1-[NH-R2
] 0-NH2 ;
at least one of X, Y or R is a linear or branched, fully or partly saturated hydrocarbon
group having 4 to 24 carbon atoms, preferably 14 to 24 carbon atoms, in particular 16 to
24 carbon atoms, for example 18 to 24 carbon atoms;
35 the acid neutralizing the amine is selected from among the monoacids offormula (II):
R'COOH (II)
- -----~,--- ---- -----------
3
where R' is a linear or branched, fully or partly saturated hydrocarbon group having 2 to
24 carbon atoms.
The inventors have surprisingly evidenced that the combination of the fully or partly
5 neutralized amine salt of the invention and of an organomolybdenum compound allows
friction phenomena to be limited whether for steel/steel, carbon coating/carbon coating or
steel/carbon coating contacts and has little or limited impact on seal degradation. In
addition, the inventors have also evidenced that the partly or fully neutralized amine salts
of the invention have better seal compatibility, in particular with seals of engines and
10 particularly motor vehicle engines, than corresponding non-neutralized amines. In the
present application, the seals are the seals employed in the design of engines, generally
polymeric seals and in particular elastomer seals, preferably fluorinated. In particular, a
lubricant composition comprising at least one partly or fully neutralized amine salt of the
invention allows limited wear of engine seals, in particular of motor vehicle engines
15 contrary to non-neutralized amines.
The amine intended to be neutralized and used in the composition of the invention is
preferably an amine meeting following formula (Ia):
R-N(X)-R1-[NHR2],-NH2 (Ia)
20 where R, X, R1
, R2 and n have the definitions given above, and
at least one of X or R is a linear or branched, fully or partly saturated hydrocarbon group
having 4 to 24 carbon atoms, preferably 14 to 24 carbon atoms, in particular 16 to 24
carbon atoms, for example 18 to 24 carbon atoms.
25 Preferably, in the compounds of formula (I) or (Ia) of the invention:
30
35
R is a linear or branched, fully or partly saturated hydrocarbon group having 14 to 24, in
particular 16 to 24, for example 18 to 24 carbon atoms; and
X is a hydrogen atom, a linear or branched alkyl group having 2 to 8 carbon atoms, a
benzyl group or group of formula-R1-[NH-R2]n-NH2 .
Preferably, in the compounds of formula (I) or (Ia) of the invention:
R is a linear or branched, fully or partly saturated hydrocarbon group having 14 to 24, in
particular 16 to 24, for example 18 to 24 carbon atoms; and
X is a hydrogen atom or group offormula-R1-[NH-R2],-NH2 .
Preferably, in the compounds of formula (I) of the invention:
4
R is a linear or branched, fully or partly saturated hydrocarbon group having 14 to 24, in
particular 16 to 24, for example 18 to 24 carbon atoms;
Y is -R1-[NH-R2]n-NH 2;
n=O;
5 R1 is CH2CH2CH2 ; and
X is CH2CH2CH2NH2 or H.
Preferably, in the compounds of formula (Ia) of the invention:
R is a linear or branched, fully or partly saturated hydrocarbon group having 14 to 24, in
10 particular 16 to 24, for example 18 to 24 carbon atoms;
n=O;
R1 is CH2CH2CH2; and
X is CH2CH,CH2NH2 or H.
15 In particularly preferred manner, the amine is selected from among the following amines:
20
25
RNHCH2CH2CH2CNH2 with R representing a linear or branched, fully or partly saturated
hydrocarbon group having 16 to 18 carbon atoms; or
N(R)(CH2CH2CH2NH2)(CH,CH2CH2NH2) with R representing a linear or branched, fully or
partly saturated hydrocarbon group having 16 to 18 carbon atoms.
In the present invention, the acid used to neutralize the amine of formula (I) or (Ia) defined
above in salt form is preferably selected from among the acids of formula (II) where R' is a
linear or branched, fully or partly saturated hydrocarbon group having 7 to 24 carbon
atoms, preferably 10 to 24, for example 14 to 20, in particular 16 to 20 carbon atoms.
In particularly preferred manner, the acid allowing neutralization of the amine of formula (I)
or (I a) is oleic acid.
The amine used in the composition of the invention is fully or partly neutralized.
30 Preferably, the molar ratio between the number of moles of nitrogen atom in the amine
and the number of moles of acid function offormula (II) is between 9:1 ancl1:1, preferably
between 5:1 and 1:1.
By organomolybdenum compound according to the invention, it is intended to designate
35 any organomolybdenum compound soluble in an oil and in particular in a base oil.
5
- - --- -- -----~-T---- - ------------
5
The organomolybdenum compound of the present invention can be selected from among
organic complexes of molybdenum such as carboxylates, esters, molybdenum amides
able to be obtained via reaction of molybdenum oxide or ammonium molybdates with fats,
glycerides, fatty acids or derivatives offatty acids (esters, amines, amides, ... ).
Preferably, the organomolybdenum compound is selected from among molybdenum
complexes free of sulfur and phosphorus, with ligands of amide type, chiefly prepared by
reaction of a molybdenum source e.g. molybdenum trioxide and of an amine derivative
with fatty acids having 4 to 28 carbon atoms for example, preferably 8 to 18 carbon atoms
i 0 such as the fatty acids contained in vegetable or animal oils.
The synthesis of such compounds is described for example in patents US4889647,
EP0546357, US5412130, EP1770153.
15 In one preferred embodiment of the invention, the organomolybdenum compound is
selected from among organic complexes of molybdenum obtained via reaction of:
(i) a fat of mono-, di- or triglyceride type, or fatty acid;
(ii) an amine source of formula (A):
20 where:
- X1 is an oxygen atom or nitrogen atom;
- X2 is an oxygen atom or nitrogen atom;
- n and m are 1 when X1 or X2 are an oxygen atom;
- n and m are 2 when X1 or X2 are a nitrogen atom;
25 (iii) and a molybdenum source selected from among molybdenum trioxide or molybdates,
preferably ammonium molybdate, in sufficient amount to provide 0.1 to 30 % molybdenum
relative to the total weight of the complex.
In one embodiment of the invention, the organic complex of molybdenum may comprise
30 from 2 to 8.5 weight% of molybdenum relative to the weight of the complex.
In one preferred embodiment of the invention, the organic complex of molybdenum is
composed of at least one of the compounds of formula (Ill) or (IV), alone or in a mixture:
where:
X1 is an oxygen atom or nitrogen atom;
X2 is an oxygen atom or nitrogen atom;
6
5 n is 1 when X1 is an oxygen atom and m is 1 when X2 is an oxygen atom;
n is 2 when X 1 is a nitrogen atom and m is 2 when X2 is a nitrogen atom;
R1 is a linear or branched, saturated or unsaturated alkyl group having 3 to 30 carbon
atoms, preferably 3 to 20 carbon atoms, advantageously 7 to 17 carbon atoms;
Hn-1 Hn-1
I o I o
~ ;---x"ll/x1~ II
R -e-N Mo N-C-Rz
1 ~l"i~
H,_, H,_, (IV)
10 where:
X1 is an oxygen atom or nitrogen atom;
X2 is an oxygen atom or nitrogen atom;
n is 1 when X1 is an oxygen atom and m is 1 when X2 is an oxygen atom;
n is 2 when X1 is a nitrogen atom and m is 2 when X2 is a nitrogen atom;
15 R1 is a linear or branched, saturated or unsaturated alkyl group having 3 to 30 carbon
atoms, preferably 3 to 20 carbon atoms, advantageously 7 to 17 carbon atoms;
R2 is a linear or branched, saturated or unsaturated alkyl group having 3 to 30 carbon
atoms, preferably 3 to 20 carbon atoms, advantageously 7 to .17 carbon atoms.
20 In one embodiment of the invention, the organic complex of molybdenum is prepared by
reaction of:
25
(i)
(ii)
(iii)
a fat of mono-, di- or triglyceride type, or fatty acid;
diethanolamine or 2-(2-aminoethyl) aminoethanol;
and a molybdenum source selected from among molybdenum trioxide or
molybdates, preferably ammonium molybdate, in sufficient amount to
provide 0.1 to 20.0 % molybdenum relative to the weight of the compleK
------------ -- ------ ---- -r- --
7
In one preferred embodiment of the invention, the organic complex of molybdenum is
composed of at least one compound of formula (111-a) or (Ill-b), alone or in a mixture:
(111-a)
5 where:
R1 is a linear or branched, saturated or unsaturated alkyl group having 3 to 30 carbon
atoms, preferably 3 to 20 carbon atoms, advantageously 7 to 17 carbon atoms,
I
~ ~N"' /0
R,-c-N~~o~
0 0
(Ill-b)
where R1 is a linear or branched, saturated or unsaturated alkyl group having 3 to 30
10 carbon atoms, preferably 3 to 20 carbon atoms, advantageously 7 to 17 carbon atoms.
As an example of sulfur-free molybdenum complexes according to the invention, mention
can be made of Molyvan 855 marketed by Vanderbilt.
15 In another embodiment, the organomolybdenum compound can be selected from among
molybdenum dithiophosphates or molybdenum dithiocarbamates.
In one preferred embodiment of the invention, the organomolybdenum compound is
selected from among molybdenum dithiocarbam;;~tes.
Molybdenum dithiocarbamate compounds (Mo- TC compounds) are complexes formed
20 of a metal core bound to one or more ligands, tile ligand being a dithiocarbamate group of
alkyls. These compounds are well known to persons skilled in the art.
In one embodiment of the invention, the Mo- TC compound may comprise from 1 to 40
%, preferably 2 to 30 %, more preferably 3 to 28 %, advantageously 4 to 15 % by weight
of molybdenum relative to the total weight of the Mo- TC compound.
25 In another embodiment of the invention, the Mo- TC compound may comprise from 1 to
40 %, preferably 2 to 30 %, more preferably 3 to 28 %, advantageously 4 to 15 % by
weight of sulfur relative to the total weight of the Mo- TC compound.
8
In another embodiment of the invention, the Mo-DTC compound can be selected from
among those having a core with two molybdenum atoms (also called dimeric Mo-DTCs)
and those having a core with three molybdenum atoms (also called trimeric Mo-DTCs).
In another embodiment of the invention, the trimeric Mo-DTC compounds meet the
5 formula Mo3S,Ln where:
k is an integer of at least 4, preferably ranging from 4 to 10, advantageously from 4 to 7;
n is an integer ranging from 1 to 4; and
L being a dithiocarbamate group of alkyls having 1 to 100 carbon atoms, preferably 1 to
40 carbon atoms, advantageously 3 to 20 carbon atoms.
10 As examples of trimeric Mo-DTC compounds according to the invention, mention can be
made of the compounds and preparation methods thereof such as described in
documents WO 98126030 et US 20031022954.
In one preferred embodiment of the invention, the Mo-DTC compound is a dimeric Mo-
15 DTC compound.
20
As examples of dimeric Mo-DTC compounds, mention can be made of the compounds
and preparation methods thereof such as described in documents EP 0757093, EP15
0719851, EP 0743354 or EP 1013749.
Dimeric Mo-DTC compounds generally correspond to the compounds of formula (V):
X3 x.
R3'- ,4-~~~~/x\11,;;--~~ /Rs
N-C • Mo Mo • C--N / ~--;.-' " / '-'.--;/ " R4 s Xe s Re
(V)
where:
R3, R,, R5, R6 , the same or different, are each independently a hydrocarbon group
selected from among alkyl, alkenyl, aryl, cycloalkyl or cycloalkenyl groups;
X3, X4 , X5 et X6 , the same or different, are each independently an oxygen atom or sulfur
25 atom.
By alkyl group in the meaning of the invention is meant a linear or branched, saturated or
unsaturated hydrocarbon group having 1 to 24 carbon atoms.
In one embodiment of the invention, the alkyl group is selected from the group formed by
30 methyl, ethyl, propyl, isopropyl, n-butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl, neopentyl,
hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl,
hexadecyl, stearyl, icosyl, docosyl , tetracosyl, triacontyl, 2-ethylhexyl, 2-butyloctyl, 2-
butyldecyl, 2-hexyloctyl, 2-hexyldecyl, 2-octyldecyl, 2-hexyldodecyl, 2-octyldodecyl, 2-
- - - - - ---------: ,------ -----------
9
decyltetradecy\, 2-dodecylhexadecyl, 2-hexadecyloctadecyl, 2-tetradecyloctadecyl,
myristyl, palmityl and stearyl.
By alkenyl group in the meaning of the present invention is meant a linear or branched
hydrocarbon group comprising at least one double bond and having 2 to 24 carbon atoms.
5 The alkenyl group can be selected from among vinyl, allyl, propenyl, butenyl, isobutenyl,
pentenyl, isopentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl,
dodecenyl, tetradecenyl and oleic.
By aryl group in the meaning of the present invention is meant a polycyclic aromatic
hydrocarbon or an aromatic group substituted or unsubstituted by an alkyl group. The a1yl
10 group may have 6 to 24 carbon atoms.
In one embodiment, the aryl group can be selected from the group formed by phenyl,
toluyl, xylyl, cumenyl, mesityl, benzyl, phenethyl, styryl, cinnamyl, benzhydryl, trityl,
ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl,
octylphenyl, nonylpheny\, decylphenyl, undecylphenyl, dodecylphenyl, phenylphenyl,
15 benzylphenyl, phenyl-styrene, p-cumylphenyl and naphthyl.
In the meaning of the present invention, the cycloalkyl groups and cycloalkenyl groups
can be selected, but not limited thereto, from the group formed by cyclopentyl, cyclohexyl,
cycloheptyl, methylcyclopentyl, methylcyclohexyl, methylcycloheptyl, cyclopentenyl,
cyclohexenyl, cycloheptenyl, methylcyclopentenyl, methylcyclohexenyl. The cycloalkyl
20 groups and cycloalkenyl groups may have 3 to 24 carbon atoms.
In one preferred embodiment of the invention, R3, R4, R5 et R6, the same or different, are
each independently an alkyl group having 4 to 18 carbon atoms, or an alkenyl group
having 2 to 24 carbon atoms.
In one embodiment of the invention, X,, X4 , Xs and Xe may be the same and may
25 represent a sulfur atom.
In another embodiment of the invention, X3 , x., Xs and X6 may be the same and may
represent an oxygen atom.
In another embodiment of the invention, X3 and X4 may represent a sulfur atom and X5
and X6 may represent an oxygen atom.
30 In another embodiment of the invention, X3 and X4 may represent an oxygen atom and X5
and X6 may represent a sulfur atom.
In another embodiment of the invention, the ratio of the number of sulfur atoms to the
number of oxygen atoms (S/0) of the Mo-DTC compound may vary from (1:3) to (3:1).
In another embodiment of the invention, the Mo-DTC compound of formula (\/) can be
35 selected from among a symmetric Mo-DTC compound, an asymmetric Mo-DTC
compound and a combination thereof.
- - ----,--,----~-'---------
10
By symmetric Mo-DTC compound according to the invention is meant a Mo-DTC
compound of formula (V) where the R3, R4 , R5 and R6 groups are the same.
By asymmetric Mo-DTC compound according to the invention is meant a Mo-DTC
compound of formula (V) where the groups R3 and R4 are the same, the groups Rs and R6
5 are the same and the groups R3 and R4 differ from the groups Rs and R6 .
In one preferred embodiment of the invention, the Mo-DTC compound is a mixture of at
least one symmetric Mo-DTC compound and at least one asymmetric Mo-DTC
compound.
In one embodiment of the invention, R3 and R4 are the same and represent an alkyl group
10 having 5 to 15 carbon atoms, and R5 and R6 are the same but differing from R3 and R4
and represent an alkyl group having 5 to 15 carbon atoms.
In one preferred embodiment of the invention R3 and R4 are the same and represent an
alkyl group having 6 to 10 carbon atoms, and R5 and Re represent an alkyl group having
1 0 to 15 carbon atoms.
15 In another preferred embodiment of the invention, R3 and R4 are the same and represent
an alkyl group having 10 to 15 carbon atoms, and R5 et R6 are an alkyl group having 6 to
10 carbon atoms.
In another preferred embodiment of the invention, R3, R4 , R5 et R6 are the same and
20 represent an alkyl group having 5 to 15 carbon atoms, preferably 8 to 13 carbon atoms.
Advantageously, the Mo-DTC compound is selected from among the compounds of
formula
(V) where:
25 - X3 and X4 are an oxygen atom;
- X5 and X6 are a sulfur atom;
- R3 is an alkyl group having 8 carbon atoms or an alkyl group having 13 carbon atoms;
- R4 is an alkyl group having 8 carbon atoms or an alkyl group having 13 carbon atoms;
- R5 is an alkyl group having 8 carbon atoms or an alkyl group having 13 carbon atoms;
30 - R6 is an alkyl group having 8 carbon atoms or an alkyl group having 13 carbon atoms.
35
Therefore, advantageously, the Mo-DTC compound is selected from among the
compounds of formula (V-a):
0 0
R3"- /-~~11/s"'-11/~~ /Rs
N-C • Mo Mo • C-N
/ "'---/ " / ""--;/ "' R4 S S S R6
i 1
(V-a)
where the groups R3 , R4 , R5 and R6 are such as defined for formula (V).
fVIore advantageously, the Mo-DTC compound is a mixture of:
5 - a Mo-DTC compound of formula (V-a) where R3 , R,, R5 et R6 represent an alkyl group
having 8 carbon atoms;
- a Mo-DTC compound of formula (V-a) where R3, R., R5 and R6 represent an alkyl group
having 13 carbon atoms; and
-a Mo-DTC compound of formula (V-a) where R3, R4 represent an alkyl group having 13
10 carbon atoms and R5 et R6 represent an alkyl group having 8 carbon atoms; and/or
- a Mo-DTC compound of formula (V-a) where R3, R4 represent an alkyl group having 8
carbon atoms and R5 et R6 represent an alkyl group having 13 carbon atoms.
As examples of Mo-DTC compounds, mention can be made of the products Molyvan L®,
Molyvan 807® or Molyvan 822® marketed by R.T Vanderbilt Company®, or the products
15 Sakura-lube 200®, Sakura-lube 165®, Sakura-lube 525® or Sakura-lube 600® marketed
by Adeka.
Preferably, the lubricant composition of the invention comprises from 0.05 to 5 %,
preferably 0.1 to 2 % by weight of the partly or fully neutralized amine salt relative to the
20 total weight of the composition.
25
Preferably, the lubricant composition of the invention comprises from 0.01 to 3 %,
preferably 0.05 to 3 % e.g. 0.1 to 2 % by weight of organomolybdenum compound relate
to the total weight of the composition.
In general, the lubricant composition of the invention may comprise any type of mineral,
synthetic or natural, animal or vegetable lubricant base oil known to skilled persons.
The base oils used in the lubricant compositions of the invention can be oils of mineral or
synthetic origin belonging to Groups I to V of the classes defined in the API classification
30 (or equivalents thereof in the A TIEL classification) (Table A) or mixtures thereof.
Saturates Sulfur Viscosity Index
content content (VI)
Group I <90% >0.03% Mineral oils 80 o;VI < 120
----------~-'""',----,--
12
Group II
Hydrocracked oils ~90% 50.03% 80 5 VI< 120
Group Ill
Hydrocracked or hydro- ~90% 5 0.03% ~ 120
isomerized oils
Group IV Polyalphaolefins (PAOs)
Group V
Esters, PAGs and other bases
not included in Groups I to IV
Table A
The mineral base oils of the invention include all types of base oil obtained by vacuum
and atmospheric distillation of crude oil, followed by refining operations such as solvent
5 extraction, deasphalting, solvent dewaxing, hydro-treatment, hydrocracking, hydroisomerization
and hydrofinishing.
Mixtures of synthetic and mineral oils can also be employed.
In general, there is no limitation as to the use of different lubricating bases to produce the
lubricating compositions of the invention, other than that they must have properties,
10 particularly of viscosity, viscosity index, sulfur content, resistance to oxidization, adapted
for use in engines or for vehicle transmissions.
The base oils of the lubricant compositions of the invention may also be selected from
among synthetic oils such as some esters of carboxylic acid and alcohols, and from
among polyalphaolefins. The polyalphaolefins used as base oils are obtained for example
15 from monomers having 4 to 32 carbon atoms e.g. from octene or decene and having
viscosity at 100 'C of between 1.5 and 15 mm2.s-1 as per standard ASTM 0445. Their
molecular weight average is generally between 250 and 3 000 as per standard ASTM
05296.
Preferably, the base oils of the present invention are selected from among the above base
20 oils having an aromatic content of between 0 and 45 %, preferably between 0 and 30 %.
The aromatic content of the oils is measured in accordance with the UV Burdett method.
Without wishing to be bound by any theory, the aromaticity of the base oil is a
characteristic allowing optimisation of the working of the polymer as a function of
temperature. The choice of an oil with low aromaticity content allows an optimum at higher
25 temperature.
Advantageously, the lubricant composition of the invention comprises at least 50 % by
weight of base oils relative to the total weight of the composition.
13
More advantageously, the lubricant composition of the invention comprises at least 60 %
by weight, even at least 70 % by weight of base oils relative to the total weight of the
composition.
More particularly advantageously, the lubricant composition of the invention comprises
5 from 60 to 99.5 % by weight of base oils, preferably 70 to 99.5 % by weight of base oils
relative to the total weight of the composition.
Numerous additives can be employed for this lubricant composition of the invention.
The preferred additives for the lubricant composition used in the invention are selected
10 from among detergents, anti-wear additives, friction modifiers differing from the
organomolybdenum compounds, e"1reme-pressure additives, dispersants, pour point
depressants, deloamers, thickeners and mixtures thereof.
Preferably the lubricant composition of the invention comprises at least one anti-wear
additive, at least one eJ-1reme pressure additive or mixtures thereof
15 Anti-wear additives and extreme-pressure additives protect rubbing surfaces by forming a
protective film adsorbed on these surfaces.
There are a large variety of anti-wear additives. Preferably, for the lubricating composition
of the invention, the anti-wear additives are selected from among phospho-sulfurized
additives such as metal alkylthiophosphates, in particular zinc alkylthiophosphates, and
20 more specifically zinc dialkyldithiophosphates or ZnDTPs. The preferred compounds have
the formula Zn((SP(S)(OR1)(0R2
))2, where R2 and R', the same or different, are each
independently an alkyl group, preferably an alkyl group having 1 to 18 carbon atoms.
Amine phosphates are also anti-wear additives that can be used in the lubricant
composition of the invention. However, the phosphorus contributed by these additives
25 may act as poison for catalytic systems of motor vehicles since these additives generate
ash. These effects can be minimised by partly substituting amine phosphates by additives
that do not contain phosphorus such as polysulfides for example, in particular sulfurized
olefins.
Advantageously the lubricating composition of the invention may comprise from 0.01 to
30 6% by weight, preferably from 0.05 to 4% by weight, more preferably from 0.1 to 2% by
weight of anti-wear additives and extreme-pressure additives relative to the total weight of
the lubricant composition,
Advantageously, the lubricant composition of the invention may comprise at least one
additional friction modifying additive differing from the organomolybdenum compounds.
35 The additional friction modifying additive can be selected from among a compound
pmviding metal elements and an ash-free compound. Among the compounds providing
14
metal elements, mention can be made of transition metal complexes such as Mo, Sb, Sn,
Fe, Cu, Zn, the ligands of which may be hydrocarbon compounds comprising atoms of
oxygen, nitrogen, sulfur or phosphorus. The ash-free friction modifying additives are
generally of organic origin and can be selected from among the monoesters of fatty acids
5 and polyols, fatty epoxides, borate fatly epoxides; or fatty acid glycerol esters. According
to the invention, the fatty compounds comprise at least one hydrocarbon group having 10
to 24 carbon atoms.
Advantageously, the lubricant composition of the invention may comprise from 0.01 to 2%
by weight, or from 0.01 to 5% by weight, preferably from 0.1 to 1.5% by weight or 0.1 to
10 2% by weight of friction modifying additive relative to the total weight of the lubricant
composition.
Advantageously, the lubricant composition of the invention may comprise at least one
antioxidant additive.
An antioxidant additive generally allows delayed degradation of the lubricant composition
15 in use. This degradation may notably translate as the formation of deposits, as the
presence of sludge or as an increase in viscosity of the lubricant composition.
Antioxidant additives particularly act as radical inhibitors or hydroperoxide decomposers.
Among the antioxidant additives frequently employed, mention can be made of antioxidant
additives of phenolic type, antioxidant additives of amino type, phosphor-sulfurized
20 antioxidant additives. Some of these antioxidant additives e.g. phospho-sulfurized
antioxidant additives may generate ash. Phenolic antioxidant additives may be ash-free or
may be in the form of neutral or basic metal salts. Antioxidant additives can be selected in
particular from among sterically hindered phenols, the esters of sterically hindered
phenols and sterically hindered phenols comprising a thioether bridge, diphenylamines,
25 diphenylamines substituted by at least one C1-C12 alkyl group, N,N'-dialkyl-aryl-diamines,
and mixtures thereof.
Preferably, according to the invention, the sterically hindered phenols are selected from
among compounds comprising a phenol group wherein at least one vicinal carbon of the
carbon carrying the alcohol function is substituted by at least one C1- C10 alkyl group,
30 preferably a c,-c. alkyl group, preferably a c4 alkyl group, preferably by the tert-butyl
group.
Amino compounds are another class of antioxidant additive that can be used, optionally in
combination with phenolic antioxidant additives. Examples of amino compounds are the
aromatic amines e.g. the aromatic amines of formula NR3R4R5 where R3 is an aliphatic
35 group or aromatic group, optionally substituted, R4 is an aromatic group, optionally
substituted, R5 is a hydrogen atom, an alkyl group, an aryl group or a group of formula
-- - ---- --------- --- ----------;-o~---
15
R6S(O)zR7 where R6 is an alkylene group or all> is meant any coating
comprising carbon. By carbon coating is notably meant diamond coatings and more
particularly nanodiamond coatings. These coatings, in particular, may be in the form of at
least one layer of nanocrystalline diamond having purity ranging from 70 to 99 %.
5 Preferably, carbon coatings are selected from among nanodiamond coatings in the form
of at least one layer of nanocrystalline diamond having purity ranging from 70 to 99 %.
preferably ranging from 70 to 97 %, advantageously 75 % and having a thickness ranging
from 0.1 to 3 !Jill, preferably ranging from 0.5 to 2 ~m, advantageously it is 1.5 iJm.
These carbon coatings can also be selected from among coatings of DLC type (Diamond
i 0 Like Carbon). Any type of DLC coating can be employed. In general, DLCs group together
a set of families of amorphous materials essentially containing carbon. Amongst these
families, hydrogenated DLCs in particular a-C:H, and non-hydrogenated DLCs in
particular a-C or ta-C, are employed.
DLCs have properties that vary as a function of their sp3 hybrid carbon content and
15 hydrogen content Some DLC variants can be doped with metal elements such as iron,
chromium or tungsten.
Compared with diamond coatings, DLC coatings generally have lesser mechanical and
thermal resistance since they are amorphous materials. On the other hand, they are
generally less rough and more especially they can be deposited at low temperature on
20 most substrates. Preferably, DLCs are hydrogenated DLCs, in particular a-C:H containing
10 to 40% hydrogen.
Advantageously, the use of the lubricant composition of the invention prevents the
aggravation and even reduces wear between two surfaces, in particular between two
25 surfaces in steel, between two carbon coated surfaces or between a steel surface and a
carbon coated surface, in particular in a vehicle engine, preferably a motor vehicle.
30
The present invention also pertains to the use of the lubricant composition of the invention
to reduce the fuel consumption of vehicles, motor vehicles in particular.
Advantageously the inventors have also evidenced that the partly or fully neutralized
amine salts of the invention have better compatibility with seals, particularly engine seals
and notably seals of motor vehicle engines, than corresponding non-neutralized amines.
In the present invention, the seals are the seals employed in engine design and are
35 generally polymeric seals, in particular elastomer seals preferably fluorinated. The
18
composition of the invention notably allows limited wear of engine seals< in particular in
motor vehicle engines, compared with non-neutralized amines<
Therefore, the present invention also relates to the use of the composition of the invention
additionally to reduce the deterioration of seals contained in a vehicle engine, preferably a
5 motor vehicle<
The present invention also concerns a method for lubricating mechanical parts, in
particular in transmissions and/or vehicle engines, particularly motor vehicle engines,
comprising at least one step to place at least one part in contact with a lubricant
10 composition of the invention< Preferably at least one of the parts is carbon coated, the
other part(s) being in steel or carbon coated<
The present invention also concerns a method for reducing friction between two surfaces
of a vehicle engine, of a motor vehicle in particular, comprising at least one step to place
15 at least one of the surfaces in contact with a lubricant composition of the invention< The
surfaces are such as defined above< In particular, the method concerns the reduction of
friction between two steel surfaces, two carbon coated surfaces or a steel surface and a
carbon coated surface< Preferably, the invention concerns a method to reduce friction
between two surfaces of a vehicle engine, in particular a motor vehicle engine, at least
20 one of the surfaces being carbon coated, comprising at least one step to place at least
one of the surfaces in contact with a lubricant composition of the invention< Preferably,
one of the surfaces is carbon coated and the other is in steel or the two surfaces are
carbon coated<
Advantageously, with the method of the invention it is possible not to aggravate and even
25 to reduce wear between two surfaces, in particular between two surfaces in steel,
between two carbon coated surfaces or between a steel surface and a carbon coated
surface, particularly in a vehicle engine and preferably a motor vehicle engine<
Advantageously, with the method of the invention it is possible not to aggravate and even
to reduce wear between two surfaces of which at least one is carbon coated<
30 The invention also concerns a method for reducing the fuel consumption of a vehicle
preferably a motor vehicle, comprising at least one step to place a mechanical part of the
vehicle engine in contact with a lubricant composition such as defined above<
The engines of the invention can be two- or four-stroke internal combustion engines< The
35 engines can be petrol engines or diesel engines intended to be powered by conventional
petrol or dieseL By « conventional petrol >> or by « conventional diesel '' in the present
- - -- -----~,--------
19
invention it is meant engines powered by fuel obtained after refining an oil of mineral
origin (e.g. crude oil). The engines may also be petrol engines or diesel engines that are
modified to be powered by a fuel containing oil derived from renewable material such as
alcohol-based fuel or biodiesel.
5 The vehicles of the invention can be light vehicles such as cars and motorbikes. The
vehicles may also be heavy vehicles, construction machinery, ships.
The transmissions of the invention can be transmissions used in light vehicles such as
motor vehicles, gear boxes in particular.
The transmissions of the invention may also be transmissions used in heavy vehicles,
10 construction machinery, in particular gear boxes or axles.
The transmissions of the invention may also be transmissions used in industrial machines,
in particular gears or gear boxes for wind turbines.
A further subject of the invention is the use of a combination of a fully or partly neutralized
15 amine salt, such as defined above, with at least one organomolybdenum compound in a
lubricant composition comprising at least one base oil to reduce friction between two
surfaces, in particular between two surfaces in steel, between a steel surface and a
carbon coated surface or between two carbon coated surfaces in an engine in particular a
vehicle engine and notably a motor vehicle engine.
20 A further subject of the invention is the use of a combination of a fully or partly neutralized
amine salt, such as defined above, with at at least one organomolybdenum compound in
a lubricant composition comprising at least one base oil, to reduce friction between two
surfaces at least one of which is carbon coated, in an engine, in particular a vehicle
engine and particularly a motor vehicle. Preferably one of the surfaces is in carbon and
25 the other is in steel or both surfaces are in carbon.
With the above use, it is also possible not to aggravate and even to reduce wear between
two surfaces in steel, between a steel surface and a carbon coated surface or between
two carbon coated surfaces, in particular in a vehicle engine and preferably a motor
vehicle engine.
30 With the above use, it is also possible not to aggravate and even to reduce wear beiJNeen
two surfaces at least one of which is carbon coated, in particular in a vehicle engine,
preferably a motor vehicle engine. Preferably, one of the surfaces is carbon coated and
the other is in steel or both surfaces are carbon coated.
The different uses mentioned in the foregoing also allow reduced deterioration of the seals
35 contained in a vehicle engine, preferably a motor vehicle.
20
The invention is described below with the aid of nonlimiting examples.
Example 1: Preparation of lubricant compositions of the invention, of comparative
lubricant compositions and evaluation of the compatibility of these compositions with the
5 seals used in motor vehicle engines.
A lubricant composition of Reference 1 was prepared in accordance with Table 1 below
(the composition is given in weight (g)).
- Base oil 1: Group Ill base oil (kinematic viscosity at 40'C measured as per standard
ASTM 0445 = 20 mm2/s);
10 - Base oil 2: Group Ill base oil (kinematic viscosity at 40'C measured as per standard
ASTM 0445 = 25 mm2/s);
- Viscosity Index improver: hydrogenated styrene/isoprene polymer;
-Additive pack: anti-wear of zinc dithiophosphate type, anti-oxidant of diphenylamine type,
detergent of calcium salicylate type (P6660® marketed by lnfineum);
15 -Pour point depressant: polymethacrylate (Lubrizol 7748® marketed by Lubrizol);
-Amine 1: neutralized fatty diamine (Duomeen TOO® marketed by Akzo Nobel);
20
-Amine 2: non-neutralized fatty diamine (Ouomeen T® marketed by Akzo Nobel);
- Friction modifier: molybdenum dithiocarbamate (Sakuralube 525® marketed by Adeka).
lubricant composition
Reference 1
Base oil1 78.0
Base oil2 3.1
Viscosity Index
5.3
improver
Additive pack 13.3
Pour point 0.3
depressant
Table 1
Lubricant compositions of the invention and comparative compositions were prepared in
accordance with Table 2 below (the compositions are given in weight (g)).
21
Composition 1
Comparative Comparative
1 2
Lubricant composition
98.6 98.6 99.6
Reference 1
Amine 1 1.0
Amine2 1.0
Friction modifier 0.4 0.4 0.4
Table 2
The compatibility of the lubricant compositions prepared with elastomer seals of RE1 type
was evaluated in accordance with standard CEC-L-39-T96 and the results obtained are
5 given in Table 3.
Composition 1 Comparative Comparative
of the invention composition 1 composition 2
Compatibility of fluorocarbon
RE 1 elastomers
% variation, breaking load -56.3% -70.1% -2.4%
compared with new seal
% variation, breaking elongation -65.5% -76.1% -0.2%
compared with new seal
% variation in volume compared +1.5% +4% +1.5%
with new seal
Table 3
The results show that the lubricant compositions of the invention (Composition 1)
comprising a combination of a neutralized amine and organomolybdenum compound have
10 better compatibility with the seals used in the engines, in particular fluorinated elastomer
seals, compared with lubricant compositions comprising a combination of a nonneutralized
amine and an organomolybdenum compound (Comparative composition 1).

CLAIMS
1.- Use, to reduce friction between two surfaces of which at least one is carbon coated, of
5 a lubricant composition comprising:
10
where:
at least one base oil;
at least one molybdenum compound;
at least one fully or partly neutralized amine salt, the amine meeting following
formula (1):
R-N(X)-Y (I)
R is a linear or branched, fully or partly saturated hydrocarbon group having 2 to 24
carbon atoms, preferably 4 to 24, more preferably 14 to 24, in particular 16 to 24, for
15 example 18 to 24 carbon atoms;
X is a hydrogen atom, a linear or branched, fully or partly saturated hydrocarbon group
having 1 to 24 carbon atoms, preferably 1 to 10 carbon atoms, in particular 1 to 8 carbon
atoms, a benzyl group or group of formula-R 1-[NH-R2]n-NH2 ;
Y is a hydrogen atom, a linear or branched, fully or partly saturated hydrocarbon group
20 having 1 to 24 carbon atoms, preferably 1 to 10 carbon atoms, in particular 1 to 8 carbon
atoms, a benzyl group or group of formula -R1-[NH-R2],-NH2 ;
n is an integer of 0 to 3, preferably 0 o 2, preferably 0 or 1;
R1 and R2
, the same or different, are a linear or branched alkyl group having 2 to 4 carbon
atoms, preferably 2 to 3 carbon atoms, preferably CH2CH2 or CH2CH2CH2;
25 at least one of X or Y is a hydrogen atom or-R1-[NH-R2]n-NH2 ;
at least one of X, Y or R is a linear or branched, fully or partly saturated hydrocarbon
group having 4 to 24 carbon atoms, preferably 14 to 24 carbon atoms, in particular 16 to
24 carbon atoms, for example 18 to 24 carbon atoms;
the acid neutralizing the amine being selected from among monoacids of formula (II)
30 R'COOH (II)
where R' is a linear or branched, fully or partly saturated hydrocarbon group having 2 to
24 carbon atoms.
2.- The use according to claim 1, wherein the amine meets following formula (Ia):
35 R-N(X)-R1-[NHR2]n-NH, (Ia)
where R, X, R1
, R2 and n have the definitions given in claim 1,
26
at least one of X or R is a linear or branched, fully or partly saturated hydrocarbon group
having 4 to 24 carbon atoms, preferably 14 to 24 carbon atoms, in particular 16 to 24
carbon atoms, for example 18 to 24 carbon atoms.
5 3.- The use according to any of claims 1 or 2, wherein:
10
15
R is a linear or branched, fully or partly saturated hydrocarbon group having 14 to 24, in
particular 16 to 24, for example 18 to 24 carbon atoms;
X is a hydrogen atom, a linear or branched alkyl group having 2 to 8 carbon atoms, a
benzyl group or group of formula -R1-[NH-R2],-NH2.
4.- The use according to any of claims 1 to 3, wherein:
R is a linear or branched, fully or partly saturated hydrocarbon group having 14 to 24, in
particular 16 to 24, for example 18 to 24 carbon atoms;
X is a hydrogen atom or group offormula -R1-[NH-R2],-NH2.
5.- The use according to any of claims 1 to 4, wherein:
R is a linear or branched, fully or partly saturated hydrocarbon group having 14 to 24, in
particular 16 to 24, for example 18 to 24 carbon atoms;
Y is -R1-[NH-R2],-NH2;
20 n=O;
R1 is CH2CHzCH2; and
X is CH2CH2CHzNH2 or H.
6.- The use according to any of claims 1 to 5, wherein the molar ratio in the composition
25 between the number of moles of nitrogen atom in the amine and the acid of formula (II) is
between 9:1 and 1:1, preferably between 5:1 and 1:1.
7.- The use according to any of claims 1 to 6, wherein R' is a linear or branched, fully or
partly saturated hydrocarbon group having 7 to 24 carbon atoms, preferably 10 to 24, for
30 example 14 to 20, in particular 16 to 20 carbon atoms.
8,- The use according to any of claims 1 to 7, wherein the organomolybdenum compound
is a molybdenum dithiocarbamate compound.
35 9.- The use according to any of claims 1 to 8, wherein the amine is selected from among
the following amines:
5
27
Ri~HCH 2CH2CH 2CI~H 2 where R is a linear or branched, fully or pa;ily saturs.ted
hydrocarbon group having 16 to 18 carbon atoms; m
N(R)(CH2CH2CH2NH2)(CH2CH2CH2NH2) where R is a linear or branched, fully or partly
saturated hydrocarbon group having 16 to i 8 carbon atoms.
iO.- The use according to any of claims 1 to 9, wherein the composition comprises from
0.05 to 5 %, preferably 0.1 to 2 % by weight of the neutralized amine relative to the total
weight of the composition.
10 11.- The use according to any of claims 1 to 10, wherein the composition comprises from
O.Oi to 3 %, preferably 0.05 to 3 %, for example 0.1 to 2 % by weight of
organomolybdenum compound relative to the total weight of the composition.
12.- The use according to any of claims 1 to i 1, wherein the composition further
15 comprises at least one anti-wear additive, preferably selected from among phosphorized,
sulfurized or phospho-sulfurized compounds, preferably from among zinc
dithiophosphates.
13.- Tile use according to any of claims 1 to 12 to reduce friction in a vehicle engine,
20 preferably a motor vehicle.
14.- The use according to any of claims 1 to 13 to reduce friction between a steel surface
and a carbon coated surface in a vehicle engine, preferably a motor vehicle.
25 15.- The use according to any of claims 1 to i 3 to reduce friction between two carbon
coated surfaces in a vehicle engine, preferably a motor vehicle.
30
16.- The use according to one of claims 1 to 15 additionally to reduce the deterioration of
seals contained in a vehicle engine, preferably a motor vehicle.